Contact plasma diagnostic system and method

Abstract

This application provides a contact plasma diagnostic system and method, applied in the field of scanning probe technology, to solve the technical problem of poor anti-interference capability in existing contact plasma diagnostic systems. Specifically, the main probe component collects the main current under the combined influence of the measured plasma and electromagnetic interference, while the compensation probe component collects the compensation current under the influence of electromagnetic interference alone. A probe data conversion circuit converts the main current and compensation current into a main voltage and a compensation voltage. Subsequent data processing restores the main current and compensation current. The difference between the main current and compensation current yields the target diagnostic current. The electron temperature of the measured plasma is determined based on the target diagnostic current and the bias voltage. Differential processing of the main current and compensation current effectively removes the influence of electromagnetic interference, improving the system's anti-interference capability. Converting the compensation current into a compensation voltage for transmission avoids large measurement errors, improving measurement accuracy and reliability.

Description

Technical Field

[0001] This application relates to the field of scanning probes, and more specifically, to a contact plasma diagnostic system and method. Background Technology

[0002] With the continuous development of aerospace technology, electric thrusters have been widely used in complex aerospace missions due to their advantages such as high specific impulse, long lifespan, and high control precision. The plasma ejected by an electric thruster during operation forms a vacuum plume (i.e., an electric propulsion plume), which contains complex plasma components, including electrons, positive ions, negative ions, and a large number of unionized neutral particles. As the understanding of plume characteristics deepens, studying more detailed plume characteristic parameters has become an inevitable trend. These parameters include the plasma potential, electron temperature, ion energy distribution, charge class, and neutral particle flow of the electric thruster plume. To obtain these plasma characteristic parameters, appropriate diagnostic methods are required. In actual electric propulsion plasma diagnostics, problems such as strong electromagnetic interference from discharge, high-frequency interference from the vacuum chamber system, and mains interference are often encountered. These interferences greatly increase the noise in the probe's detection signal, making it impossible for existing plasma diagnostic systems to diagnose the electron temperature accurately, or even obtain any valuable signal; the effective detection signal is completely submerged in electromagnetic interference.

[0003] Currently, plasma diagnostic systems often rely on single methods combined with experimental experience to reduce the impact of electromagnetic interference (EMI). For example, some systems use metal shielding sleeves, which can reduce EMI to some extent, but their effectiveness is limited in environments with strong EMI. Other systems incorporate EMI suppression designs into the diagnostic circuitry to enhance its immunity. However, because the diagnostic circuitry's function is relatively simple, a large amount of interference noise is collected along with the signal, causing significant difficulties in post-processing of experimental data and sometimes even resulting in the signal being completely overwhelmed by noise. These EMI suppression methods are only effective in environments with weak EMI. In the application scenarios of contact-based diagnostics for electric propulsion plasma, the operation of the electric thruster typically generates strong EMI, making the EMI suppression capability of the plasma diagnostic system poor, difficult to obtain usable measurement signals, and thus unable to accurately diagnose the electron temperature of the plasma. Summary of the Invention

[0004] The purpose of this application is to provide a contact plasma diagnostic system and method to solve the technical problem of poor anti-interference capability of existing contact plasma diagnostic systems.

[0005] On one hand, this application provides a contact plasma diagnostic system, including: a probe body, a probe data conversion circuit, and a diagnostic device; the main probe component in the probe body is in contact with the plasma to be measured, and the compensation probe component in the probe body is not in contact with the plasma to be measured; the main probe component and the compensation probe component are respectively connected to the probe data conversion circuit; the diagnostic device is connected to the measurement end of the probe data conversion circuit.

[0006] The probe body is used to collect the main current under the combined action of the measured plasma and electromagnetic interference through the main probe component, and to collect the compensation current under the action of electromagnetic interference only through the compensation probe component.

[0007] The probe data conversion circuit is used to provide bias voltage to the main probe component and the compensation probe component, and convert the main current collected by the main probe component into the main voltage according to a preset conversion ratio, and convert the compensation current collected by the compensation probe component into the compensation voltage according to a preset conversion ratio.

[0008] The diagnostic equipment is used to detect the main voltage and compensation voltage. Based on the preset conversion ratio, the main voltage and compensation voltage are restored to obtain the main current and compensation current. The difference between the main current and compensation current is used to obtain the target diagnostic current, which is the actual diagnostic current after removing electromagnetic interference. The electron temperature of the plasma under test is determined based on the target diagnostic current and the bias voltage.

[0009] Optionally, the probe body includes: a main probe component, a compensation probe component, a ceramic tube, and a metal shielding sleeve;

[0010] The main probe component and the compensation probe component are sealed in the ceramic tube along the extension direction of the ceramic tube. One end of the main probe component extends out of the front end of the ceramic tube, and the compensation probe component is disposed inside the ceramic tube.

[0011] The outer wall of the ceramic tube is covered with a metal shielding sleeve.

[0012] Optionally, the main probe assembly includes three main probes; the compensation probe assembly includes three compensation probes.

[0013] Three main probes and three compensation probes are alternately and evenly spaced along the circumferential direction of the ceramic tube.

[0014] Optionally, multiple probe channels are provided inside the ceramic tube along the extension direction; the probe channels are used to set the main probe or compensation probe.

[0015] Multiple probe channels are evenly spaced along the circumferential direction of the ceramic tube.

[0016] Optionally, the probe body may also include: an insulating isolation sleeve;

[0017] The insulating sleeve has a probe body insertion channel and a wire channel group arranged sequentially along its extension direction; the wire channel group includes multiple wire exit channels, which are evenly spaced along the circumferential direction of the insulating sleeve.

[0018] The rear end of the metal shielding sleeve is inserted into the probe body of the insulating isolation sleeve through the channel, and the main probe and the compensation probe are respectively connected to the data conversion circuit through the corresponding wires.

[0019] Optionally, the probe data conversion circuit includes: a main data conversion circuit and a compensation data conversion circuit;

[0020] The main data conversion circuit includes: a first power supply, a second power supply, a first resistor, a second resistor, a first capacitor, a second capacitor, a third capacitor, and a fourth capacitor;

[0021] The positive terminal of the first power supply is connected to the positive terminal of the second power supply and the first main probe among the three main probes. The negative terminal of the first power supply is connected to the second main probe among the three main probes through the first resistor. The negative terminal of the second power supply is connected to the third main probe among the three main probes through the second resistor. The first capacitor is connected in parallel across the two ends of the first power supply, the second capacitor is connected in parallel across the two ends of the second power supply, the third capacitor is connected in parallel across the two ends of the first resistor, and the fourth capacitor is connected in parallel across the two ends of the second resistor.

[0022] The compensation data conversion circuit includes: a third power supply, a fourth power supply, a third resistor, a fourth resistor, a fifth capacitor, a sixth capacitor, a seventh capacitor, and an eighth capacitor;

[0023] The positive terminal of the third power supply is connected to the positive terminal of the fourth power supply and the first compensation probe among the three compensation probes. The negative terminal of the third power supply is connected to the second compensation probe among the three compensation probes through the third resistor. The negative terminal of the fourth power supply is connected to the third compensation probe among the three compensation probes through the fourth resistor. The fifth capacitor is connected in parallel across the three power supplies, the sixth capacitor is connected in parallel across the two power supplies, the seventh capacitor is connected in parallel across the two resistors, and the eighth capacitor is connected in parallel across the four resistors.

[0024] Optionally, the diagnostic equipment includes: a data measurement device and a diagnostic module; the data measurement device is connected to the measurement terminals of the main data conversion circuit and the compensation data conversion circuit, respectively; the diagnostic module is connected to the output terminal of the measurement device.

[0025] The data measurement device is used to detect the main voltage output by the main data conversion circuit and the compensation voltage output by the compensation data conversion circuit, and transmits the main voltage and compensation voltage to the diagnostic module.

[0026] The diagnostic module is used to restore the main voltage to obtain the main current according to the conversion ratio of the main data conversion circuit, and restore the compensation voltage to obtain the compensation current according to the conversion ratio of the auxiliary data conversion circuit; the difference between the main current and the compensation current is used to obtain the target diagnostic current, where the target diagnostic current is the actual diagnostic current after removing electromagnetic interference; the electron temperature of the plasma under test is determined according to the target diagnostic current and the bias voltage.

[0027] Optionally, the data measurement device includes: a first differential probe, a second differential probe, a third differential probe, a fourth differential probe, and an oscilloscope;

[0028] The first input terminal of the first differential probe is connected to the first terminal of the third capacitor, the second input terminal of the first differential probe is connected to the second terminal of the third capacitor, and the output terminal of the first differential probe is connected to the oscilloscope.

[0029] The first input terminal of the second differential probe is connected to the first terminal of the fourth capacitor, the second input terminal of the second differential probe is connected to the second terminal of the fourth capacitor, and the output terminal of the second differential probe is connected to the oscilloscope.

[0030] The first input terminal of the third differential probe is connected to the first terminal of the seventh capacitor, the second input terminal of the third differential probe is connected to the second terminal of the seventh capacitor, and the output terminal of the third differential probe is connected to the oscilloscope.

[0031] The first input terminal of the fourth differential probe is connected to the first terminal of the eighth capacitor, the second input terminal of the fourth differential probe is connected to the second terminal of the eighth capacitor, and the output terminal of the fourth differential probe is connected to the oscilloscope.

[0032] The communication terminal of the oscilloscope is connected to the input terminal of the diagnostic module.

[0033] On the other hand, embodiments of this application provide a contact plasma diagnostic method, applied in the diagnostic equipment of the aforementioned contact plasma diagnostic system, the method comprising:

[0034] Obtain the main voltage and compensation voltage;

[0035] Based on the preset conversion ratio, the main voltage and compensation voltage are restored to obtain the main current and compensation current.

[0036] The target diagnostic current is obtained by subtracting the main current and the compensation current, where the target diagnostic current is the actual diagnostic current after removing electromagnetic interference.

[0037] The electron temperature of the plasma under test is determined based on the target diagnostic current and the preset bias voltage.

[0038] Optionally, after obtaining the main voltage and compensation voltage, the following may also be included:

[0039] When the compensation voltage is less than the preset voltage threshold, the main voltage is restored according to the preset conversion ratio to obtain the main current;

[0040] The electron temperature of the plasma under test is determined based on the main current and the preset bias voltage.

[0041] The beneficial effects of the embodiments of this application are as follows:

[0042] In this embodiment, a non-contact compensation probe component is additionally set in the probe body to collect the compensation current generated solely by electromagnetic interference. The difference between the main current collected by the main probe component (under the combined effects of plasma and electromagnetic interference) and the compensation current is processed to effectively remove the influence of electromagnetic interference, obtaining the actual diagnostic current after removing electromagnetic interference as the target diagnostic current. The electron temperature of the plasma under test is determined based on the target diagnostic current and the bias voltage, improving the anti-interference capability of the contact plasma diagnostic system. This allows the contact plasma diagnostic system to operate normally in environments with strong electromagnetic interference, effectively overcoming the limitations of traditional plasma diagnostic systems in strong interference environments and significantly improving the accuracy and applicability of the contact plasma diagnostic system. Furthermore, the probe data conversion circuit converts the main current into a main voltage and the compensation current into a compensation voltage for signal transmission. This avoids the problem of large measurement errors caused by the small magnitudes of both the main current and the compensation current, improving measurement accuracy and reliability.

[0043] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the first system framework of the contact plasma diagnostic system in the embodiments of this application;

[0046] Figure 2 This is a schematic diagram of the probe body in an embodiment of this application;

[0047] Figure 3This is a schematic diagram of the insulating sleeve in an embodiment of this application;

[0048] Figure 4 This is a schematic diagram of a second system framework for the contact plasma diagnostic system in this application embodiment;

[0049] Figure 5 This is a first overview flowchart of the contact plasma diagnostic method in the embodiments of this application;

[0050] Figure 6 This is a second overview flowchart of the contact plasma diagnostic method in the embodiments of this application. Detailed Implementation

[0051] To make the objectives, technical solutions, and beneficial effects of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] It should be noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. Furthermore, the term "and / or" used in this application describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0053] This application provides a contact plasma diagnostic system, see [link / reference]. Figure 1 As shown, the contact plasma diagnostic system provided in this application embodiment includes at least: a probe body 100, a probe data conversion circuit 110, and a diagnostic device 120; the main probe component 101 in the probe body 100 is in contact with the plasma to be measured, and the compensation probe component 102 in the probe body 100 is not in contact with the plasma to be measured; the main probe component 101 and the compensation probe component 102 are respectively connected to the probe data conversion circuit 110; the diagnostic device 120 is connected to the measurement terminal of the probe data conversion circuit 110.

[0054] The probe body 100 is used to collect the main current under the combined action of the plasma under test and electromagnetic interference through the main probe component 101, and to collect the compensation current under the action of electromagnetic interference only through the compensation probe component 102.

[0055] The probe data conversion circuit 110 is used to provide bias voltage to the main probe component 101 and the compensation probe component 102, and convert the main current collected by the main probe component 101 into the main voltage according to a preset conversion ratio, and convert the compensation current collected by the compensation probe component 102 into the compensation voltage according to a preset conversion ratio.

[0056] The diagnostic device 120 is used to detect the main voltage and compensation voltage, restore the main voltage and compensation voltage according to the preset conversion ratio, and obtain the main current and compensation current; the difference between the main current and compensation current is used to obtain the target diagnostic current, wherein the target diagnostic current is the actual diagnostic current after removing electromagnetic interference; the electron temperature of the plasma under test is determined according to the target diagnostic current and the bias voltage.

[0057] In such Figure 1 In the contact plasma diagnostic system shown, the detection end of the main probe component 101 in the probe body 100 is exposed to the measurement environment of the plasma under test. The main probe component 101 collects the main current under the combined influence of the plasma under test and electromagnetic interference, under the action of a first bias voltage provided by the probe data conversion circuit 110. The main probe component 101 can be designed with multiple probes to improve the efficiency and accuracy of current collection. The number of main currents is determined by the number of probes in the main probe component 101. The detection end of the compensation probe component 102 in the probe body 100 is isolated from the measurement environment of the plasma under test. It collects the compensation current under the influence of only electromagnetic interference, under the action of a second bias voltage provided by the probe data conversion circuit 110. The compensation probe component 102 can also be designed with multiple probes, and the number of probes in the compensation probe component 102 is consistent with the number of probes in the main probe component 101. The number of compensation currents is determined by the number of probes in the compensation probe component 102. The probes in the main probe component 101 and the compensation probe component 102 can both use tungsten wires with a diameter range of 0.1~0.5mm, but it is necessary to ensure that the tungsten wires used in the probes of a set of devices have the same diameter, and 0.3mm tungsten wires are usually selected.

[0058] The probe data conversion circuit 110 provides a first bias voltage to the main probe component 101 to collect the main current, and a second bias voltage to the compensation probe component 102 to collect the compensation current. Furthermore, since both the main current and the compensation current are relatively small, the probe data conversion circuit 110 can perform signal type conversion and signal amplification according to a preset conversion ratio. Specifically, the small main current is multiplied by the first conversion ratio to convert it into a stable main voltage, and the small compensation current is multiplied by the second conversion ratio to convert it into a stable compensation voltage. This replaces the method of measuring a smaller current with the method of measuring a larger voltage, thereby improving the accuracy and reliability of the measurement. The conversion between current and voltage in the probe data conversion circuit 110 can be achieved through a circuit composed of components such as resistors and capacitors. The first bias voltage and the second bias voltage can be equal, and the first conversion ratio and the second conversion ratio can be equal. For ease of calculation and symmetry considerations, the first bias voltage and the second bias voltage are usually set to be equal, and the first conversion ratio and the second conversion ratio are usually set to be equal.

[0059] The diagnostic device 120 is equipped with a voltage detection device to detect the main voltages and compensation voltages output by the probe data conversion circuit 110. After obtaining the main voltages and compensation voltages, the main voltage is divided by a first conversion ratio to obtain the main current; the compensation voltage is divided by a second conversion ratio to obtain the compensation current. When there are multiple main currents and compensation currents, the compensation current corresponding to the main current can be determined in advance based on the distribution position of the probes in the compensation probe component 102 of the main probe component 101. The actual diagnostic current for removing electromagnetic interference, i.e., the target diagnostic current, is obtained by subtracting the corresponding compensation current from the main current. The calculation method for the electron temperature is determined based on the number of probes in the main probe component 101 and the compensation probe component 102, and the electron temperature of the measured plasma is calculated based on the target diagnostic current and the bias voltage.

[0060] Thus, the contact plasma diagnostic system provided in this application, by additionally setting a non-contact compensation probe component in the probe body, collects the compensation current generated solely by electromagnetic interference. The main current collected by the main probe component under the combined effects of plasma and electromagnetic interference is differentially processed with the compensation current, thereby effectively removing the influence of electromagnetic interference. The actual diagnostic current after removing electromagnetic interference is obtained as the target diagnostic current. The electron temperature of the plasma under test is determined based on the target diagnostic current and the bias voltage, improving the anti-interference capability of the contact plasma diagnostic system. This allows the contact plasma diagnostic system to operate normally in environments with strong electromagnetic interference, effectively overcoming the limitations of traditional plasma diagnostic systems in strong interference environments, and significantly improving the accuracy and applicability of the contact plasma diagnostic system. Furthermore, the probe data conversion circuit is used to convert the main current into a main voltage and the compensation current into a compensation voltage before transmitting the detection signal. This avoids the problem of large measurement errors caused by the small magnitudes of both the main current and the compensation current, improving the accuracy and reliability of the measurement. Furthermore, this system is applicable not only to steady-state plasma but also to transient plasma diagnostics. It has a simple structure, is easy to assemble, and helps improve the overall accuracy of three-probe diagnostics of electronic temperature, demonstrating broad application prospects and practical value.

[0061] In practical implementation, the probe body in a contact plasma diagnostic system can adopt various structures to achieve its function; see [reference needed]. Figure 2 As shown, the probe body includes at least: a main probe component 101, a compensation probe component 102, a ceramic tube 103, and a metal shielding sleeve 104;

[0062] The main probe component 101 and the compensation probe component 102 are sealed in the ceramic tube 103 along the extension direction of the ceramic tube 103. One end of the main probe component 101 extends out of the front end of the ceramic tube 103, and the compensation probe component 102 is disposed inside the ceramic tube 103.

[0063] The outer wall of the ceramic tube 103 is covered with a metal shielding sleeve 104.

[0064] In such Figure 2In the probe body shown, the main probe component 101 and the compensation probe component 102 are sealed within the ceramic tube 103 along its extension direction. One end of the main probe component 101 extends beyond the front end of the ceramic tube 103. The main probe collects the main current under the combined influence of the measured plasma and electromagnetic interference through this extended end. The other end of the main probe component 101 is electrically connected to the probe data conversion circuit via a wire, so that the probe data conversion circuit provides a bias voltage to the main probe component 101 and receives the main current collected by the main probe component 101. One end of the compensation probe component 102 is sealed within the ceramic tube 103. The compensation probe collects the main current under the influence of electromagnetic interference only through this end. The other end of the compensation probe component 102 is electrically connected to the probe data conversion circuit via a wire, so that the probe data conversion circuit provides a bias voltage to the compensation probe component 102 and receives the main current collected by the compensation probe component 102. The ceramic tube 103 serves as a carrier for the main probe component 101 and the compensation probe component 102, providing support and protection. Furthermore, the ceramic tube 103 possesses excellent insulation and high-temperature resistance, ensuring stable operation of the probe body even in environments with severe external interference. The interior of the ceramic tube 103 can be filled with insulating adhesive to achieve insulation isolation between the main probe component 101 and the compensation probe component 102. A metal shielding sleeve 104 covers the outer wall of the ceramic tube 103 to shield against external electromagnetic interference, effectively reducing the influence of external electromagnetic fields on the probe body and improving diagnostic accuracy. The metal shielding sleeve 104 is connected to ground.

[0065] Thus, existing technologies using complex anti-interference methods (such as placing the entire probe within a Faraday cage) would drastically increase the size of the three probes, further amplifying the problem of insufficient spatial resolution, and would also cause significant interference to the plume field distribution of the electric thruster. These two unacceptable negative impacts mean that, under strong electromagnetic interference, improving the anti-electromagnetic interference capabilities of the three probes may do more harm than good. In contrast, this application, while employing a technical shielding sleeve to shield against external electromagnetic interference, only adds a compensation probe isolated from the plasma to the original main probe component. This improves the anti-electromagnetic interference capability without sacrificing the probe's size and spatial resolution. The miniaturized design of the probe body minimizes its disruption to the plume field, maintaining a spatial resolution comparable to or even better than existing products.

[0066] In practice, single-probe and dual-probe methods require scanning voltage for diagnosis. When plasma changes drastically, the scanning voltage must be fast enough for accurate measurement. Using single-probe or dual-probe methods for diagnosis makes it difficult to balance scanning speed and measurement accuracy. The three-probe method, however, does not require scanning voltage. Instead, it places three probes in the plasma at different potentials and directly measures plasma properties using voltage and current based on Kirchhoff's laws. This method is well-suited for plasma measurements where parameters change rapidly over time. (See also...) Figure 2 As shown, the main probe component 101 includes three main probes; the compensation probe component 102 includes three compensation probes.

[0067] Three main probes and three compensation probes are alternately and evenly spaced along the circumferential direction of the ceramic tube 103.

[0068] In practical applications, alternating and uniformly distributing the main probe and compensation probe around the circumference of the ceramic tube 103 allows for a more comprehensive capture of spatial changes in the plasma, making it easier to detect local variations within the plasma. This reduces measurement deviations caused by uneven probe placement, improving measurement accuracy and reliability. The alternating arrangement of the main probe and compensation probe can partially cancel out measurement errors, such as those caused by differences in probe position, shape, or material.

[0069] Alternatively, the main probe and compensation probe can also be configured using the following schemes:

[0070] Three main probes are evenly spaced along the circumferential direction of the ceramic tube, and compensation probes are set one-to-one on the inner or outer side of the main probes. The ends of the compensation probes and the corresponding main probes are set on the same diameter.

[0071] In practical applications, the method of setting up compensation probes one-to-one on the inside or outside of the main probe makes the probe structure simpler and clearer, facilitating installation and debugging. Because the probe structure is simple and symmetrical, maintenance and replacement are easier when a probe malfunctions or needs to be replaced.

[0072] In practical implementation, the extension length of the main probe and the relative distribution of the main probe and compensation probe are crucial to the accuracy of plasma diagnostics. Excessive or insufficient extension length of the main probe, as well as misalignment in its distribution, can lead to measurement errors. The application of insulating adhesive firmly fixes the main probe and compensation probe within the ceramic tube, making direct adjustment of their extension length and position difficult. Traditional adjustment methods, such as manually adjusting the probe position or length, become impractical in the presence of insulating adhesive. Therefore, probe channels can be created inside the ceramic tube to house the main probe and compensation probe, achieving fixed positions for the main probe and compensation probe and mutual insulation between the probes. Specifically, multiple probe channels are arranged along the extension direction inside the ceramic tube; these channels are used to house the main probe or compensation probe.

[0073] Multiple probe channels are evenly spaced along the circumferential direction of the ceramic tube.

[0074] In practical applications, the distribution of multiple probe channels is specifically set according to the distribution of the main probe and compensation probe. Multiple probe channels are evenly spaced along the circumferential direction of the ceramic tube. Each probe channel contains one probe, with the main probe and compensation probe alternately positioned within each channel. This uniform distribution design helps ensure that the spatial distribution of the main probe and compensation probe in the plasma is also uniform, reducing measurement errors caused by uneven probe positions, thereby improving measurement accuracy and reliability. Alternatively, the probe channels containing the main probe can also be evenly spaced along the circumferential direction of the ceramic tube, with the compensation probe channels corresponding one-to-one to the probe channels containing the main probe, positioned inside or outside the probe channels containing the main probe. The ends of the compensation probe channels and their corresponding main probe channels are aligned on the same diameter, achieving another distribution scheme for the probes and compensation probes.

[0075] In practical applications, the number of probe channels in the ceramic tube is determined based on the total number of main probes and compensation probes. The probe channels in the ceramic tube can be cylindrical channels, with a diameter slightly larger than that of the main probe and compensation probe. Both ends of the cylindrical channel containing the main probe are not closed, while one end of the cylindrical channel containing the compensation probe is closed, ensuring that the compensation probe is not in contact with the plasma being measured. One end of the cylindrical channel containing the compensation probe is sealed with insulating adhesive, or it is sealed during the molding process of the ceramic tube. Furthermore, the cylindrical channels can be designed with tight fits, threaded connections, or fixing clips to ensure the probes are securely fixed within the ceramic tube.

[0076] Optionally, the probe channel in the ceramic tube can be a tapered channel, and the end where the main probe and the compensation probe are connected to the probe data conversion circuit corresponds to the end with the larger diameter of the tapered channel. Both ends of the tapered channel of the main probe are not closed, while the end with the smaller diameter of the cylindrical channel of the compensation probe is closed.

[0077] In one possible implementation, see [reference] Figure 2 and Figure 3 As shown, the probe body in the contact plasma diagnostic system may also include: an insulating sleeve 105;

[0078] The insulating sleeve 105 is provided with a probe body insertion channel 106 and a wire channel group 107 in sequence along its extension direction; the wire channel group 107 includes multiple wire exit channels, which are evenly spaced along the circumferential direction of the insulating sleeve 105.

[0079] The rear end of the metal shielding sleeve 104 is inserted into the probe body insertion channel of the insulating isolation sleeve 105, and the main probe and the compensation probe are respectively connected to the data conversion circuit through the corresponding wires passing out of the channel.

[0080] exist Figure 2 and Figure 3In the insulating sleeve 105 shown, the rear end of the metal shielding sleeve 104 corresponds to the wiring end of each main probe and each compensation probe component to the probe data conversion circuit. The main probe and compensation probe component are connected to the probe data conversion circuit through soldered wires. Insulation treatment is required between the solder joints of the probes. Therefore, the insulating sleeve 105 needs to be fitted onto the rear end of the metal shielding sleeve 104 of the probe body. The insulating sleeve 105 is a hollow tubular structure. One end of the insulating sleeve 105 is provided with a probe body fitting hole 108 corresponding to the probe body fitting channel 106, and the other end of the insulating sleeve 105 is provided with multiple wire exit holes 109 corresponding to multiple wire exit channels. It is made of a material with high temperature resistance, chemical corrosion resistance, and good electrical insulation performance. Along its extension direction, the insulating sleeve 105 has a connected probe body fitting channel 106 and wire channel group 107 inside. The probe body fitting channel 106 is used to fit onto the rear end of the metal shielding sleeve 104 and ensure a stable connection between the metal shielding sleeve 104 and the insulating sleeve 105. The lead channel group 107 consists of multiple lead exit channels, the arrangement of which can correspond to the arrangement of the probe channels. The leads can be coaxial shielded wires. Specifically, the multiple lead exit channels can be evenly spaced along the circumferential direction of the insulating sleeve 105. Each lead exit channel is used to connect the main probe to the probe data conversion circuit wires, and to the compensation pin to the probe data conversion circuit wires. This insulating sleeve prevents contact between probe solder joints, ensuring mutual insulation between probes and preventing current leakage through unexpected paths. This is crucial for ensuring the safety and reliability of the plasma diagnostic system, and also reduces the impact of electromagnetic interference and noise on probe signals, thereby improving the accuracy and reliability of measurement results.

[0081] In one possible implementation, multiple aviation connectors may also be provided in the probe body;

[0082] Each main probe and each compensation probe are connected to the probe data conversion circuit via different aviation connectors.

[0083] In practical applications, welding probes made of tungsten wire and thin coaxial shielded wire cores presents certain challenges, and the solder joints are prone to irregularity. This results in slight differences in the contact resistance values ​​of the measurement circuits corresponding to each probe, leading to measurement errors. Connecting the probes and thin coaxial shielded wire cores via aviation connectors simplifies the wiring, provides a more robust connection, and maximizes the uniformity of contact resistance.

[0084] In practical implementation, the probe data conversion circuit in a contact plasma diagnostic system can adopt various structures to achieve its function; see [reference needed]. Figure 4As shown, the probe data conversion circuit 110 includes at least: a main data conversion circuit 111 and a compensation data conversion circuit 112;

[0085] The main data conversion circuit 111 includes: a first power supply V1, a second power supply V2, a first resistor R1, a second resistor R2, a first capacitor C1, a second capacitor C2, a third capacitor C3, and a fourth capacitor C4.

[0086] The positive terminal of the first power supply V1 is connected to the positive terminal of the second power supply V2 and the first main probe P1 of the three main probes. The negative terminal of the first power supply V1 is connected to the second main probe P2 of the three main probes through the first resistor R1. The negative terminal of the second power supply V2 is connected to the third main probe P3 of the three main probes through the second resistor R2. The first capacitor C1 is connected in parallel across the two ends of the first power supply V1, the second capacitor C2 is connected in parallel across the two ends of the second power supply V2, the third capacitor C3 is connected in parallel across the two ends of the first resistor R1, and the fourth capacitor C4 is connected in parallel across the two ends of the second resistor R2.

[0087] The compensation data conversion circuit 112 includes: a third power supply V3, a fourth power supply V4, a third resistor R3, a fourth resistor R4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, and an eighth capacitor C8.

[0088] The positive terminal of the third power supply V3 is connected to the positive terminal of the fourth power supply V4 and the first compensation probe P4 of the three compensation probes. The negative terminal of the third power supply V3 is connected to the second compensation probe P5 of the three compensation probes through the third resistor R3. The negative terminal of the fourth power supply V4 is connected to the third compensation probe P6 of the three compensation probes through the fourth resistor R4. The fifth capacitor C5 is connected in parallel across the three power supplies V3, the sixth capacitor C6 is connected in parallel across the four power supplies V4, the seventh capacitor C7 is connected in parallel across the three resistor R3, and the eighth capacitor C8 is connected in parallel across the four resistor R4.

[0089] exist Figure 4In the probe data conversion circuit 110 shown, the first power supply V1 is used to apply voltage between the first main probe P1 and the second main probe P2; the second power supply V2 is used to apply voltage between the third main probe P3 and the second main probe P2. The output voltages of the first power supply V1 and the second power supply V2 are equal, both being the first bias voltage. The first main probe P1 is used to collect the first main current, the second main probe P2 is used to collect the second main current, and the third main probe P3 is used to collect the third main current. The first resistor R1 is used to convert the second main current collected by the second main probe P2 into the first main voltage, and the second resistor R2 is used to convert the third main current collected by the third main probe P3 into the second main voltage. The first capacitor C1 and the second capacitor C2 are used to stabilize the output voltage of the power supply, which can achieve the function of stabilizing the voltage and improving the probe measurement accuracy. The third capacitor C3 and the fourth capacitor C4 are used to filter out voltage fluctuations across the resistors, which can effectively reduce the sudden change in voltage across the resistors during discharge, prevent the sudden change from damaging the measuring device, and also filter out high-frequency noise. The main data conversion circuit 111 and the compensation data conversion circuit 112 have the same structure. Correspondingly, the third power supply V3 is used to apply voltage between the first compensation probe P4 and the second compensation probe P5; the fourth power supply V4 is used to apply voltage between the third compensation probe P6 and the second compensation probe P5. The output voltages of the third power supply V3 and the fourth power supply V4 are equal, both being the second bias voltage. The first bias voltage and the second bias voltage are the same. The first compensation probe P4 is used to collect the first compensation current, the second compensation probe P5 is used to collect the second compensation current, and the third compensation probe P6 is used to collect the third compensation current. The third resistor R3 is used to convert the second compensation current collected by the second compensation probe P5 into the first compensation voltage, and the fourth resistor R4 is used to convert the third compensation current collected by the third compensation probe P6 into the second compensation voltage. The fifth capacitor C5 and the sixth capacitor C6 are used to stabilize the output voltage of the power supply, which can achieve the function of stabilizing the voltage and improve the probe measurement accuracy. The seventh capacitor C7 and the eighth capacitor C8 are used to filter out voltage fluctuations across the resistor, which can effectively reduce the sudden change in voltage across the resistor during discharge, prevent the sudden change from damaging the measuring device, and also filter out high-frequency noise.

[0090] In practical applications, the first bias voltage and the second bias voltage can be set according to different measurement conditions. The potential difference between the first main probe P1 and the second main probe P2, and the potential difference between the first main probe P1 and the third main probe P3, determines the magnitude of the current in the main data conversion circuit 111. The applied first bias voltage should be used to make the second main probe P2 and the third main probe P3 operate in the ion saturation current region as much as possible. At this time, the current received by the second main probe P2 and the third main probe P3 is close to the ion saturation current. The larger the current, the smaller the influence of the interference signal on the measurement result. Similarly, the applied second bias voltage should be used to make the second compensation probe P5 and the third compensation probe P6 operate in the ion saturation current region as much as possible. The resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 are selected in the range of 400~2000 Ω, usually 1000 Ω; the capacitance values ​​of the third capacitor C3, the fourth capacitor C4, the seventh capacitor C7, and the eighth capacitor C8 are selected in the range of 800~1200 pF, usually 1000 pF; the capacitance values ​​of the first capacitor C1, the second capacitor C2, the fifth capacitor C5, and the sixth capacitor C6 are selected in the range of 2000~3000 uF, usually 2200 uF; the first power supply V1, the second power supply V2, the third power supply V3, and the fourth power supply V4 are usually selected as DC power supplies, which can be adjusted between 20~80 V. For the diagnosis of electric thrusters, 26~30 V is usually selected.

[0091] In practical implementation, the diagnostic equipment in a contact plasma diagnostic system can adopt various structures to achieve its functions; see [reference needed]. Figure 4 As shown, the diagnostic device 120 includes at least: a data measurement device 121 and a diagnostic module 122; the data measurement device 121 is connected to the measurement terminal of the main data conversion circuit 111 and the measurement terminal of the compensation data conversion circuit 112, respectively; the diagnostic module 122 is connected to the output terminal of the measurement device.

[0092] The data measurement device 121 is used to detect the main voltage output by the main data conversion circuit 111 and the compensation voltage output by the compensation data conversion circuit 112, and transmit the main voltage and compensation voltage to the diagnostic module 122.

[0093] The diagnostic module 122 is used to restore the main voltage to obtain the main current according to the conversion ratio of the main data conversion circuit 111, and restore the compensation voltage to obtain the compensation current according to the conversion ratio of the auxiliary data conversion circuit; the difference between the main current and the compensation current is used to obtain the target diagnostic current, wherein the target diagnostic current is the actual diagnostic current after removing electromagnetic interference; and the electron temperature of the plasma under test is determined according to the target diagnostic current and the bias voltage.

[0094] exist Figure 4In the contact plasma diagnostic system shown, the data measurement device 121 is connected to the measurement terminal of the probe data conversion circuit 110, and detects in real time the main voltages output by the main data conversion circuit 111 and the compensation voltages output by the compensation data conversion circuit 112, and transmits them to the diagnostic module 122 respectively. (See reference...) Figure 4 As shown, the main voltages detected by the data measuring device 121 are the first main voltage across the first resistor R1 and the second main voltage across the second resistor R2; the compensation voltages detected by the data measuring device 121 are the first compensation voltage across the third resistor R3 and the second compensation voltage across the fourth resistor R4. The diagnostic module 122 can restore each main voltage and each compensation voltage according to the conversion ratio of the probe data conversion circuit 110, and obtain each main current and each compensation current. (See reference...) Figure 4 As shown, the conversion ratio of the probe data conversion circuit 110 is determined based on the corresponding resistor values. The first main voltage divided by the resistance of the first resistor R1 yields the second main current collected by the second main probe P2, and the second main voltage divided by the resistance of the second resistor R2 yields the third main current collected by the third main probe P3. The first compensation voltage divided by the resistance of the third resistor R3 yields the second compensation current collected by the second compensation probe P5, and the second compensation voltage divided by the resistance of the fourth resistor R4 yields the third compensation current collected by the third compensation probe P6. Subtracting the compensation current from the main current yields the target diagnostic current, thus eliminating electromagnetic interference and more accurately reflecting the true state of the plasma. Subtracting the second compensation current from the second main current yields the first target diagnostic current, and subtracting the third compensation current from the third main current yields the second target diagnostic current. The calculation method for the electron temperature of the measured plasma needs to be determined based on the number of probes in the main probe component; refer to [reference needed]. Figure 4 As shown, the main probe component has a three-probe structure, and the electron temperature can be calculated using implicit equations under strong electromagnetic interference conditions.

[0095] (1)

[0096] Where I2 is the second main current, I3 is the third main current, I5 is the second compensation current, I6 is the third compensation current, and T e V is the electron temperature. d2 V is the voltage output by the first power supply V1. d3 This is the voltage output from the second power supply V2.

[0097] In one possible implementation, the diagnostic module can employ different plasma diagnostic methods under different electromagnetic interference intensities. The diagnostic module is also used to determine whether the compensation voltage is less than a preset voltage threshold after acquiring the main voltage and compensation voltage.

[0098] If not, the main voltage and compensation voltage are restored according to the preset conversion ratio to obtain the main current and compensation current; the difference between the main current and compensation current is used to obtain the target diagnostic current, where the target diagnostic current is the actual diagnostic current after removing electromagnetic interference; the electron temperature of the plasma under test is determined according to the target diagnostic current and the preset bias voltage.

[0099] If so, the main voltage is restored according to the preset conversion ratio to obtain the main current; the electron temperature of the plasma under test is determined according to the main current and the preset bias voltage.

[0100] In practical applications, the diagnostic module has a pre-set voltage threshold. When at least one compensation voltage is greater than the voltage threshold, it corresponds to a situation with strong electromagnetic interference. In this case, the difference between the main current and the compensation current is used to obtain the target diagnostic current. The target diagnostic current and the preset bias voltage are then substituted into the above formula (1) to calculate the electron temperature of the plasma being measured. When none of the compensation voltages are greater than the voltage threshold, it corresponds to a situation with weak electromagnetic interference or no electromagnetic interference. In this case, the electron temperature of the plasma being measured can be directly calculated based on the restored main current. Specifically, taking... Figure 4 Taking the system shown as an example, the second main voltage divided by the resistance of the first resistor yields the second main current collected by the second main probe, and the third main voltage divided by the resistance of the second resistor yields the third main current collected by the third main probe. Since the main probe component has a three-probe structure, the electron temperature can be calculated using implicit equations under conditions of no electromagnetic interference and weak electromagnetic interference.

[0101] (2)

[0102] Where I2 is the second main current, I3 is the third main current, and T e V is the electron temperature. d2 V is the voltage output by the first power supply V1. d3 This is the voltage output from the second power supply V2.

[0103] Thus, in environments with no or weak electromagnetic interference, contact plasma diagnostics are performed using data measured by the main probe component, and electromagnetic interference and noise are reduced by using comprehensive anti-interference measures and an improved probe data conversion circuit. In environments with strong electromagnetic interference, contact plasma diagnostics are performed using data measured by the main probe component and the compensation probe component, and the influence of electromagnetic interference is eliminated by using a compensation method, and electromagnetic interference and noise are reduced by using comprehensive anti-interference measures and an improved probe data conversion circuit.

[0104] For specific implementation, please refer to Figure 4As shown, the data measurement device 121 includes: a first differential probe 123, a second differential probe 124, a third differential probe 125, a fourth differential probe 126, and an oscilloscope 127;

[0105] The first input terminal of the first differential probe 123 is connected to the first terminal of the third capacitor C3, the second input terminal of the first differential probe 123 is connected to the second terminal of the third capacitor C3, and the output terminal of the first differential probe 123 is connected to the oscilloscope 127.

[0106] The first input terminal of the second differential probe 124 is connected to the first terminal of the fourth capacitor C4, the second input terminal of the second differential probe 124 is connected to the second terminal of the fourth capacitor C4, and the output terminal of the second differential probe 124 is connected to the oscilloscope 127.

[0107] The first input terminal of the third differential probe 125 is connected to the first terminal of the seventh capacitor C7, the second input terminal of the third differential probe 125 is connected to the second terminal of the seventh capacitor C7, and the output terminal of the third differential probe 125 is connected to the oscilloscope 127.

[0108] The first input terminal of the fourth differential probe 126 is connected to the first terminal of the eighth capacitor C8, the second input terminal of the fourth differential probe 126 is connected to the second terminal of the eighth capacitor C8, and the output terminal of the fourth differential probe 126 is connected to the oscilloscope 127.

[0109] The communication terminal of the oscilloscope 127 is connected to the input terminal of the diagnostic module 122.

[0110] In practical applications, the first differential probe 123 is used to acquire the voltage across the first resistor R1, i.e., the first main voltage; the second differential probe 124 is used to acquire the voltage across the second resistor R2, i.e., the second main voltage; the third differential probe 125 is used to acquire the voltage across the third resistor R3, i.e., the first compensation voltage; and the fourth differential probe 126 is used to acquire the voltage across the fourth resistor R4, i.e., the second compensation voltage. The communication terminal of the oscilloscope 127 is connected to the input terminal of the diagnostic module 122, so that the oscilloscope 127 can display the voltage detected by each differential probe in real time and send each main voltage and each compensation voltage to the diagnostic module 122.

[0111] Based on the same inventive concept, this application also provides a contact plasma diagnostic method, applied to the diagnostic equipment of the aforementioned contact plasma diagnostic system, see reference. Figure 5 As shown, the contact plasma diagnostic method includes:

[0112] Step 101: Obtain the main voltage and compensation voltage.

[0113] Step 102: Based on the preset conversion ratio, restore the main voltage and compensation voltage to obtain the main current and compensation current.

[0114] Step 103: Subtract the main current and the compensation current to obtain the target diagnostic current, where the target diagnostic current is the actual diagnostic current after removing electromagnetic interference.

[0115] Step 104: Determine the electron temperature of the plasma under test based on the target diagnostic current and the preset bias voltage.

[0116] In one possible implementation, see [reference] Figure 6 As shown, after obtaining the main voltage and compensation voltage, the process also includes:

[0117] Step 201: When the compensation voltage is less than the preset voltage threshold, restore the main voltage according to the preset conversion ratio to obtain the main current.

[0118] Step 202: Determine the electron temperature of the plasma under test based on the main current and the preset bias voltage.

[0119] It should be noted that although several units or sub-units of the device have been mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of this application, the features and functions of two or more units described above can be embodied in one unit. Conversely, the features and functions of one unit described above can be further divided and embodied by multiple units.

[0120] Furthermore, although the operations of the method of this application are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0121] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0122] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. A contact plasma diagnostic system, characterized in that, include: The system comprises a probe body, a probe data conversion circuit, and a diagnostic device; the main probe component in the probe body is in contact with the plasma being measured, and the compensation probe component in the probe body is in non-contact with the plasma being measured; the main probe component and the compensation probe component are respectively connected to the probe data conversion circuit; and the diagnostic device is connected to the measurement terminal of the probe data conversion circuit. The probe body is used to collect the main current under the combined action of the measured plasma and electromagnetic interference through the main probe component, and to collect the compensation current under the action of electromagnetic interference only through the compensation probe component. The probe data conversion circuit is used to provide bias voltage for the main probe component and the compensation probe component, and convert the main current collected by the main probe component into the main voltage according to a preset conversion ratio, and convert the compensation current collected by the compensation probe component into the compensation voltage according to a preset conversion ratio. The diagnostic device is used to detect the main voltage and the compensation voltage, restore the main voltage and the compensation voltage according to a preset conversion ratio, and obtain the main current and the compensation current; the difference between the main current and the compensation current is used to obtain the target diagnostic current, wherein the target diagnostic current is the actual diagnostic current after removing electromagnetic interference; the electron temperature of the plasma under test is determined according to the target diagnostic current and the bias voltage. The probe body includes: a main probe component, a compensation probe component, a ceramic tube, and a metal shielding sleeve; The main probe component and the compensation probe component are sealed in the ceramic tube along the extension direction of the ceramic tube. One end of the main probe component extends out of the front end of the ceramic tube, and the compensation probe component is disposed inside the ceramic tube. The outer wall of the ceramic tube is covered with the metal shielding sleeve; The main probe component includes three main probes; the compensation probe component includes three compensation probes. The three main probes and the three compensation probes are arranged alternately and at uniform intervals along the circumferential direction of the ceramic tube.

2. The contact plasma diagnostic system as described in claim 1, characterized in that, The ceramic tube has multiple probe channels arranged inside along the extending direction; the probe channels are used to set the main probe or the compensation probe. The multiple probe channels are evenly spaced along the circumferential direction of the ceramic tube.

3. The contact plasma diagnostic system as described in claim 1, characterized in that, The probe body also includes: an insulating sleeve; The insulating sleeve is provided with a probe body insertion channel and a wire channel group in sequence along its extension direction; the wire channel group includes multiple wire exit channels, which are evenly spaced along the circumferential direction of the insulating sleeve. The rear end of the metal shielding sleeve is fitted into the probe body fitting channel of the insulating isolation sleeve, and the main probe and the compensation probe are respectively connected to the data conversion circuit through the corresponding wires passing through the channel.

4. The contact plasma diagnostic system as described in any one of claims 1-3, characterized in that, The probe data conversion circuit includes: a main data conversion circuit and a compensation data conversion circuit; The main data conversion circuit includes: a first power supply, a second power supply, a first resistor, a second resistor, a first capacitor, a second capacitor, a third capacitor, and a fourth capacitor; The positive terminal of the first power supply is connected to the positive terminal of the second power supply and the first main probe of the three main probes. The negative terminal of the first power supply is connected to the second main probe of the three main probes through the first resistor. The negative terminal of the second power supply is connected to the third main probe of the three main probes through the second resistor. The first capacitor is connected in parallel across the two ends of the first power supply, the second capacitor is connected in parallel across the two ends of the second power supply, the third capacitor is connected in parallel across the two ends of the first resistor, and the fourth capacitor is connected in parallel across the two ends of the second resistor. The compensation data conversion circuit includes: a third power supply, a fourth power supply, a third resistor, a fourth resistor, a fifth capacitor, a sixth capacitor, a seventh capacitor, and an eighth capacitor; The positive terminal of the third power supply is connected to the positive terminal of the fourth power supply and the first compensation probe of the three compensation probes. The negative terminal of the third power supply is connected to the second compensation probe of the three compensation probes through the third resistor. The negative terminal of the fourth power supply is connected to the third compensation probe of the three compensation probes through the fourth resistor. The fifth capacitor is connected in parallel across the two ends of the third power supply, the sixth capacitor is connected in parallel across the two ends of the fourth power supply, the seventh capacitor is connected in parallel across the two ends of the third resistor, and the eighth capacitor is connected in parallel across the two ends of the fourth resistor.

5. The contact plasma diagnostic system as described in claim 4, characterized in that, The diagnostic device includes: a data measurement device and a diagnostic module; the data measurement device is connected to the measurement terminal of the main data conversion circuit and the measurement terminal of the compensation data conversion circuit respectively; the diagnostic module is connected to the output terminal of the measurement device. The data measurement device is used to detect the main voltage output by the main data conversion circuit and the compensation voltage output by the compensation data conversion circuit, and transmit the main voltage and the compensation voltage to the diagnostic module; The diagnostic module is used to restore the main voltage to obtain the main current according to the conversion ratio of the main data conversion circuit, and restore the compensation voltage to obtain the compensation current according to the conversion ratio of the auxiliary data conversion circuit; the difference between the main current and the compensation current is used to obtain the target diagnostic current, wherein the target diagnostic current is the actual diagnostic current after removing electromagnetic interference; and the electron temperature of the plasma under test is determined according to the target diagnostic current and the bias voltage.

6. The contact plasma diagnostic system as described in claim 5, characterized in that, The data measurement device includes: a first differential probe, a second differential probe, a third differential probe, a fourth differential probe, and an oscilloscope; The first input terminal of the first differential probe is connected to the first terminal of the third capacitor, the second input terminal of the first differential probe is connected to the second terminal of the third capacitor, and the output terminal of the first differential probe is connected to the oscilloscope. The first input terminal of the second differential probe is connected to the first terminal of the fourth capacitor, the second input terminal of the second differential probe is connected to the second terminal of the fourth capacitor, and the output terminal of the second differential probe is connected to the oscilloscope. The first input terminal of the third differential probe is connected to the first terminal of the seventh capacitor, the second input terminal of the third differential probe is connected to the second terminal of the seventh capacitor, and the output terminal of the third differential probe is connected to the oscilloscope. The first input terminal of the fourth differential probe is connected to the first terminal of the eighth capacitor, the second input terminal of the fourth differential probe is connected to the second terminal of the eighth capacitor, and the output terminal of the fourth differential probe is connected to the oscilloscope. The communication terminal of the oscilloscope is connected to the input terminal of the diagnostic module.

7. A contact plasma diagnostic method, characterized in that, The method, applied in a diagnostic device of a contact plasma diagnostic system as described in any one of claims 1-6, comprises: Obtain the main voltage and compensation voltage; Based on the preset conversion ratio, the main voltage and the compensation voltage are restored to obtain the main current and the compensation current; The target diagnostic current is obtained by subtracting the main current and the compensation current, wherein the target diagnostic current is the actual diagnostic current after removing electromagnetic interference; The electron temperature of the plasma under test is determined based on the target diagnostic current and the preset bias voltage.

8. The contact plasma diagnostic method as described in claim 7, characterized in that, After obtaining the main voltage and the compensation voltage, the process further includes: When the compensation voltage is less than a preset voltage threshold, the main voltage is restored according to a preset conversion ratio to obtain the main current; The electron temperature of the plasma under test is determined based on the main current and the preset bias voltage.

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