A multi-parameter coaxial co-point diagnostic probe for magnetic field and plasma characteristics

Abstract

The present invention relates to a coaxial common-point diagnostic probe for multi-parameters of magnetic field and plasma characteristics, comprising: a three-dimensional magnetic field measurement module support rod, an inductor coil, a signal transmission cable and a fixing groove for the inductor coil, a plasma metal probe, and an embedded plasma measurement module support rod. The three-dimensional magnetic field measurement module uses a slender rod with a square cross-section as a support, and rectangular grooves are opened on three adjacent side surfaces, and inductors are placed to achieve the measurement of three-dimensional transient magnetic fields. A circular through hole is opened in the center of the square cross-section, and a plasma measurement module with an aluminum oxide shielding layer is embedded to achieve transient measurement of plasma electron temperature, electron density and other characteristics. Since the three-dimensional magnetic field measurement module and the plasma measurement module are in the same spatial position in the axial direction, they can be considered as data collection at the same point and time in space during measurement, reducing the temporal and spatial non-uniformity in the measurement of transient working conditions.

Description

Technical Field

[0001] The present invention relates to the fields of plasma diagnosis, dynamic three-dimensional magnetic field measurement and electric propulsion, and in particular to a coaxial common-point diagnostic probe for multi-parameters of magnetic field and plasma characteristics. Background Art

[0002] With the completion of the Tiangong core module of China's space station, space electric propulsion has gradually entered the public eye. The Tiangong core module is equipped with four Hall-effect electric propulsion engines, marking the first use of a space electric propulsion system in human manned spaceflight. This represents a quiet transformation of space propulsion systems, marking their transition from laboratory prototypes to mature, reliable, and practical products. While the first use of the Hall-effect electric propulsion system is groundbreaking, it still presents an urgent need for high-performance, high-power electric propulsion systems. Compared to traditional continuous-flow thrusters such as Hall and ion thrusters, the inductively pulsed plasma thruster (IPP) is an electrodeless electromagnetic thruster that avoids electrode ablation and offers advantages such as high specific impulse, high efficiency, high power, and a diverse working fluid. However, IPP thrusters, particularly those with field-reversed configurations, operate in a pulsed mode, resulting in rapid plasma generation and dissipation, which in turn causes fluctuations in the electric and magnetic fields in space. During operation, the physical properties of plasma and the distribution of electromagnetic fields in space significantly influence the thrust, efficiency, specific impulse, and total impulse of thrusters. However, current measurement methods measure magnetic field and plasma properties separately, assuming that the plasma properties are identical across different pulses. The spatial distribution is ultimately determined by measuring different points in space under different pulses. However, in practice, it is impossible to guarantee that each pulse is identical, resulting in numerous systematic errors. An effective measurement device is urgently needed to perform transient measurements of all physical quantities of the dynamic magnetic field and plasma physical properties at the same point in space at the same time, enabling evaluation of thruster performance and subsequent improvements. Summary of the Invention

[0003] In response to the above problems, the purpose of the present invention is to provide a coaxial and common-point diagnostic probe for multi-parameter magnetic field and plasma characteristics. By rationally designing the measurement module size, the three-dimensional magnetic field measurement module and the plasma measurement module can achieve coaxial measurement, ensuring that the three-dimensional magnetic field measurement module and the plasma measurement module measure the physical quantities at the same point in space in engineering measurements, and realizing the requirement of transient measurement of the dynamic three-dimensional magnetic field and all physical characteristics of the plasma at the same point in space at the same time.

[0004] A coaxial common-point diagnostic probe for multi-parameter magnetic field and plasma characteristics, characterized by comprising: a three-dimensional magnetic field measurement module support rod, an inductance coil, a signal transmission cable and an inductance coil fixing groove, a plasma metal probe, and an embedded plasma measurement module support rod. The 3D magnetic field measurement module consists of a support rod, an inductor coil, a signal transmission cable, and a groove for fixing the inductor coil. The plasma measurement module consists of a plasma metal probe and the embedded support rod of the plasma measurement module. The 3D magnetic field measurement module and the plasma measurement module are coaxially arranged. The cross-section of the support rod of the 3D magnetic field measurement module is square, and its length is determined by measurement requirements. Slots pointing in three different spatial directions (X, Y, and Z) are opened on three connected side surfaces of the support rod of the 3D magnetic field measurement module, and the inductor coil is fixed therein. Transient measurement of the 3D magnetic field is performed according to Faraday's law of electromagnetic induction. Multiple pairs of magnetic field detection inductor coils can be arranged at different axial lengths depending on the usage. A circular through-hole is opened in the center of the square cross-section of the 3D magnetic field measurement module support rod. The diameter of the circular hole is determined by the outer diameter of the embedded plasma support rod. The requirement is that the plasma measurement module can be embedded and fixed along the circular hole. The inductor coil and plasma metal probe are the measurement functional structures of the 3D magnetic field measurement module and the plasma measurement module, respectively. They are arranged in the same axial position to ensure that the physical quantities measured by the 3D magnetic field measurement module and the plasma measurement module can be considered to be the same point in space during engineering measurement.

[0005] The support rod of the three-dimensional magnetic field measurement module is made of polyetheretherketone engineering plastic (PEEK) or other high-strength and easy-to-process plastic materials. The square cross-section size of the support rod of the three-dimensional magnetic field measurement module is as small as possible and controlled within 10mm×10mm.

[0006] The inductor coil is a standard packaged coil with uniform specifications, which is convenient for installation, calibration and adjustment.

[0007] The plasma metal probe is made of tungsten or other metals, and three are evenly distributed on the circumference. The diameter of the tungsten wire is selected to be 0.3mm-0.5mm, and the spacing is about 1-2mm to reduce the mutual influence between different probes.

[0008] The signal transmission cable and inductor coil fixing grooves are opened on three adjacent side surfaces of the 3D magnetic field measurement module support rod, with one side surface remaining unused. The fixing grooves have a rectangular cross-section, and their orientation, length, width, and depth are determined by the inductor coil used. The smaller the inductor size, the better, with the maximum side length less than 5mm. The normal direction of the inductor coil is generally parallel to the long side of the inductor. To ensure that the normal directions of the three inductor coils point in three different spatial directions (X, Y, and Z), the normal vectors of the left and right side inductor coils are parallel and perpendicular to the axis of the 3D magnetic field measurement module support rod, pointing in the Z and X directions respectively. The normal vector of the top surface inductor coil is perpendicular to the axis of the 3D magnetic field measurement module support rod, pointing in the Y direction. This enables three-dimensional magnetic field measurement in X, Y, and Z space. If multiple sets of 3D magnetic field measurement points are set axially, the axial spacing can be determined according to the specific usage, but the slot shape, inductor coil fixing method, and magnetic field measurement method must be consistent. A slot with a width and depth of less than 3mm is opened in the 3D magnetic field measurement module support rod to fix the transmission signal cable.

[0009] The embedded plasma measurement module support rod is made of alumina or other high-strength, non-metallic material with good insulation properties. The size of the circular through-hole in the center of the square cross-section of the 3D magnetic field measurement module support rod is determined based on the size of the embedded plasma measurement module support rod. The outer diameter of the embedded plasma measurement module support rod is preferably 3-5mm. The diameter of the hole is slightly larger than the outer diameter of the support rod to ensure smooth insertion and fixation of the plasma measurement module. The hole is recessed 1-2mm to ensure consistent axial spacing between the two probes.

[0010] The inductive coil in the three-dimensional magnetic field measurement module and the plasma metal probe in the plasma measurement module must have the same axial position to ensure that in engineering measurements, the three-dimensional magnetic field measurement module and the plasma measurement module can be considered to measure the physical quantity at the same point in space.

[0011] The beneficial effects of the present invention are:

[0012] 1. The present invention can realize three-dimensional dynamic measurement of spatial magnetic field by reasonably arranging the relative positions of inductive coils on the support surface of the measurement module, and can expand the magnetic field measurement points according to needs.

[0013] 2. The present invention realizes the coaxial configuration of different measurement modules by rationally designing the measurement module size and organically combining the plasma measurement module with the three-dimensional magnetic field measurement module, and ensures that the measurement probes are in the same axial position, ensuring that in engineering measurements, the three-dimensional magnetic field measurement module and the plasma measurement module can be considered to measure the physical quantity at the same point in space.

[0014] 3. The present invention proposes a coaxial, co-point, multi-parameter diagnostic probe for magnetic field and plasma characteristics. By rationally setting the size and relative position of the measurement modules, the coaxial configuration of the three-dimensional magnetic field measurement module and the plasma measurement module is achieved. This ensures that in engineering measurements, the physical quantities measured by the three-dimensional magnetic field measurement module and the plasma measurement module can be considered to be at the same point in space. Furthermore, the transient change information of the magnetic field and plasma physical characteristics of the pulsed plasma thruster at the same point in space under the pulsed operating mode can be obtained, so as to evaluate the thruster's performance and carry out subsequent optimization and improvement work. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 An isometric view of a coaxial, co-point diagnostic probe for multi-parameters of magnetic field and plasma characteristics according to an embodiment of the present invention.

[0016] Figure 2a This is a side surface schematic diagram of a fixed measurement Z-axis induction coil according to an embodiment of the present invention.

[0017] Figure 2b This is a schematic side view of a fixed measurement Y-axis induction coil according to an embodiment of the present invention. Figure 2c This is a schematic side view of a fixed measurement X-axis induction coil according to an embodiment of the present invention.

[0018] Figure 2d This is a schematic diagram of an unused side surface according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic front view of the measurement module head according to an embodiment of the present invention.

[0020] The numbers in the figure are explained as follows:

[0021] Three-dimensional magnetic field measurement module support rod 1, inductance coil 2, signal transmission cable and inductance coil fixing groove 3, plasma metal probe 4, embedded plasma measurement module support rod 5. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is described in detail below with reference to embodiments.

[0023] like Figure 1 As shown, a coaxial and co-point diagnostic probe for magnetic field and plasma characteristics of an embodiment of the present invention includes: a three-dimensional magnetic field measurement module support rod 1, an inductor coil 2, a signal transmission cable and an inductor coil fixing groove 3, a plasma metal probe 4, and an embedded plasma measurement module support rod 5. Specifically:

[0024] like Figure 3As shown, the three-dimensional magnetic field measurement module support rod 1 is made of polyetheretherketone engineering plastic (PEEK) with a cross-section of 10mm×10mm square. The distance between the three side surface inductance coils is minimized as much as possible. The length is 120mm, but it can also be extended as needed. The three-dimensional magnetic field measurement module support rod serves as a support for the three-dimensional magnetic field measurement module.

[0025] The inductor coil is a standard packaged coil with a specification of 3.3mm×2.8mm×2.2mm. Standard coils of other sizes and specifications can also be used, but unified specifications are conducive to installation, calibration and adjustment.

[0026] like Figure 3 As shown, the plasma metal probe is made of tungsten, and three of them are evenly distributed on the circumference. The diameter of the tungsten wire is 0.5 mm, and the spacing is about 1 mm to reduce the mutual influence between different probes.

[0027] like Figures 2a-2d As shown, the signal transmission cable and the inductor coil fixing grooves are opened on three adjacent side surfaces of the three-dimensional magnetic field measurement support rod, and the remaining side surface is not used, as shown in FIG. Figure 2d As shown, the cross-section of the fixed groove is rectangular. Its orientation, length, width, and depth are determined by the inductor coil used, and are 3.5mm×3mm×2.5mm. The normal direction of the inductor coil is generally parallel to the long side of the inductor. In order to make the normal directions of the three inductor coils point in the three different directions of space X, Y, and Z, the normal vector of the left-side coil is parallel to the axis of the support rod of the three-dimensional magnetic field measurement module and points in the Z direction, as shown in the figure. Figure 2a As shown; the normal vector of the right face coil is perpendicular to the axis of the three-dimensional magnetic field measurement module support rod and points to the X direction, as shown Figure 2c As shown; the normal vector of the upper surface coil is perpendicular to the axis of the three-dimensional magnetic field measurement module support rod and points to the Y direction, as shown Figure 2b As shown, three-dimensional magnetic field measurement in X, Y, and Z space is possible. If multiple sets of three-dimensional magnetic field measurement points are set axially, the axial spacing can be determined based on the specific application. However, the slot pattern, coil fixing method, and magnetic field measurement method must be consistent. A 2.5mm x 2.5mm groove is also created on the support surface to secure the transmission signal cable.

[0028] like Figure 3 As shown, the embedded plasma measurement module support rod is made of alumina. The support rod has an outer diameter of 4.3mm and a hole diameter of 4.5mm, allowing the plasma measurement module to be embedded and fixed. The rod is recessed 2mm to ensure the axial distance between the two probes is consistent.

[0029] The design and use of a multi-parameter coaxial, co-point diagnostic probe for magnetic field and plasma characteristics are as follows: a three-dimensional magnetic field measurement module consists of a support rod 1, an inductor 2, a signal transmission cable, and a retaining groove 3 for the inductor. The plasma measurement module consists of a plasma metal probe 4 and an embedded support rod 5. The inductor coil of the three-dimensional magnetic field measurement module and the metal probe of the plasma measurement module are coaxially arranged and axially aligned, ensuring that the physical quantities measured by the three-dimensional magnetic field measurement module and the plasma measurement module are considered to be the same point in space during engineering measurements. The diagnostic probe is fixed to a three-dimensional displacement slide, and the relative position of the diagnostic probe and thruster is recorded. When a pulsed plasma thruster is ignited at a frequency of 500kHz, the gaseous working fluid is ionized and plasma is formed. The ionized electrons in the plasma undergo directed angular motion in the thruster, generating angular currents. According to Ampere's law, as the angular currents form and disappear, the background magnetic field changes. Move the diagnostic probe to different positions and use an oscilloscope to record the potential change data at that position. The data read by the three-dimensional magnetic field measurement module can be used to calculate the background magnetic field change, which is generally tens to hundreds of gauss, and the derived angular current is several thousand amperes. The data read by the plasma measurement module can be used to calculate the plasma electron density, electron temperature, plasma space potential and other physical quantities at that point. Generally, the electron density is 10 16 to 10 19 per cubic meter, the electron temperature is tens to dozens of electron volts, and the space potential is tens of volts relative to the ground. The oscilloscope's acquisition frequency can be as high as GHz. Therefore, the transient change information of the magnetic field and plasma physical characteristics of the pulsed plasma thruster at the same point in space under the pulsed working mode can be obtained, so as to evaluate the thruster's performance and carry out subsequent optimization and improvement work.

[0030] It should be understood that the above content is a further detailed description of the present invention in combination with a specific preferred embodiment, and it cannot be determined that the specific embodiments of the present invention are limited to this. For ordinary technicians in the technical field to which the present invention belongs, they can make several simple deductions or substitutions without departing from the concept of the present invention, which should be regarded as belonging to the scope of patent protection determined by the submitted claims of the present invention.

Claims

1. A multi-parameter coaxial co-point diagnostic probe for magnetic field and plasma characteristics, characterized in that: include: The three-dimensional magnetic field measurement module includes a support rod, an inductive coil, a signal transmission cable and a fixing groove for the inductive coil, a plasma metal probe, and an embedded plasma measurement module support rod. The three-dimensional magnetic field measurement module includes the support rod, the inductive coil, the signal transmission cable, and the fixing groove for the inductive coil. The plasma measurement module includes the plasma metal probe and the embedded plasma measurement module support rod. The three-dimensional magnetic field measurement module and the plasma measurement module are coaxially arranged.

2. The multi-parameter coaxial co-point diagnostic probe for magnetic field and plasma characteristics according to claim 1, characterized in that: The cross-section of the support rod of the three-dimensional magnetic field measurement module is square, and the length is determined according to the measurement requirements; slots pointing to three different directions of space X, Y, and Z are opened on the three connected side surfaces of the support rod of the three-dimensional magnetic field measurement module, and the inductor coils are fixed in them, and multiple pairs of magnetic field detection inductor coils are set at different axial lengths.

3. The multi-parameter coaxial co-point diagnostic probe for magnetic field and plasma characteristics according to claim 1, characterized in that: A circular through hole is opened in the center of the square cross-section of the three-dimensional magnetic field measurement module support rod. The diameter of the circular hole is determined according to the outer diameter of the embedded plasma support rod, and the plasma measurement module is embedded and fixed along the circular hole; the inductive coil and the plasma metal probe are the measurement structures of the three-dimensional magnetic field measurement module and the plasma measurement module respectively, and are configured in the same axial position to ensure that the three-dimensional magnetic field measurement module and the plasma measurement module measure the physical quantity at the same point in space during engineering measurement.

4. A magnetic field and plasma characteristic multi-parameter coaxial co-point diagnostic probe according to claim 1, 2 or 3, characterized in that: The support rod of the three-dimensional magnetic field measurement module is made of a high-strength and easily processed plastic material, including polyetheretherketone engineering plastic PEEK. The square cross-sectional size of the support rod of the three-dimensional magnetic field measurement module is controlled within 10mm×10mm.

5. The multi-parameter coaxial co-point diagnostic probe for magnetic field and plasma characteristics according to claim 1, characterized in that: The inductor coil is a standard packaged coil.

6. The multi-parameter coaxial co-point diagnostic probe for magnetic field and plasma characteristics according to claim 1, characterized in that: The plasma metal probe is made of tungsten metal, and three of them are evenly distributed on the circumference. The diameter of the tungsten wire is 0.3mm-0.5mm, and the spacing is about 1-2mm.

7. The multi-parameter coaxial co-point diagnostic probe for magnetic field and plasma characteristics according to claim 1, 2 or 3, characterized in that: The signal transmission cable and inductor coil fixing grooves are opened on three adjacent side surfaces of the three-dimensional magnetic field measurement module support rod, and the remaining side surface is not used. The cross-section of the fixing groove is rectangular, and the direction, length, width and depth are determined by the inductor coil used. The maximum side length of the inductor is less than 5mm.

8. The multi-parameter coaxial co-point diagnostic probe for magnetic field and plasma characteristics according to claim 1, characterized in that: The normal direction of the inductor coil is parallel to the long side of the inductor. In order to make the normal directions of the three inductor coils point to three different directions of space X, Y, and Z, the normal vectors of the inductor coils on the left and right sides are parallel and perpendicular to the axial direction of the support rod of the three-dimensional magnetic field measurement module, pointing in the Z direction and X direction respectively. The normal vector of the inductor coil on the top surface is perpendicular to the axial direction of the support rod of the three-dimensional magnetic field measurement module and pointing in the Y direction, realizing three-dimensional magnetic field measurement in X, Y, and Z space.

9. The multi-parameter coaxial co-point diagnostic probe for magnetic field and plasma characteristics according to claim 8, characterized in that: If multiple sets of three-dimensional magnetic field measurement points are set axially, the axial spacing will be determined according to the specific usage conditions, but the slot form, the inductor coil fixing method and the magnetic field measurement method must be consistent; and a slot with a width and depth of less than 3mm shall be opened on the support rod of the three-dimensional magnetic field measurement module to fix the transmission signal cable.

10. The multi-parameter coaxial co-point diagnostic probe for magnetic field and plasma characteristics according to claim 1, characterized in that: The embedded plasma measurement module support rod is made of non-metallic materials with high strength and good insulation effect, including alumina; the size of the circular through hole in the center of the square cross-section of the three-dimensional magnetic field measurement module support rod is determined according to the size of the embedded plasma measurement module support rod, and the outer diameter of the embedded plasma measurement module support rod is 3-5mm. The diameter of the hole is larger than the outer diameter of the support rod, so that the plasma measurement module can be smoothly embedded and fixed, with a recess of 1-2mm, to ensure that the axial distance between the two probes is consistent.

Images