Radio frequency circuit for generating ionization wave in inert gas

Abstract

The utility model relates to a radio frequency circuit for generating ionization waves in inert gas, belongs to the crossing field of plasma control technology and radio frequency circuits, and aims to solve the problems of high observation cost, difficulty in continuous observation, difficulty in decoupling influence of various parameters and the like in the conventional ionization wave research method. Comprising an over-current protection module, a constant-current control module, a self-oscillation network, a bias control module and a modulation signal generator, and is combined with a transparent closed container filled with low-pressure xenon / krypton / argon. The constant current technology stabilizes current, electromagnetic coupling parameters are independently adjustable, modulation signals are forced to intermittently oscillate, visual ionization waves are formed in the container, the circuit state is monitored in real time through a non-contact detection network, the problems that in the prior art, equipment is complex, parameters are coupled, and observation cost is high are solved, and the ionization wave research device and method are simplified.

Description

Technical Field

[0001] This utility model relates to a radio frequency circuit that generates ionization waves in an inert gas, belonging to the intersection of plasma control technology and radio frequency circuits. Background Technology

[0002] In the current scientific and technological field, plasma has a wide range of applications, demonstrating potential value in many important fields such as biomedicine, aerospace, and magnetic confinement fusion. During plasma generation, high ionization rate regions exhibit temporal and spatial periodicity, possessing wave characteristics; this phenomenon is called ionization waves. However, current research on ionization waves faces many limitations:

[0003] 1. High observation costs and inconvenience for continuous observation: Current research on ionizing waves mainly relies on ICCD cameras. ICCD cameras are expensive, increasing the economic cost of research. At the same time, this observation method makes it difficult to continuously observe changes in ionizing waves, which is not conducive to in-depth research on the dynamic changes of ionizing waves at different times.

[0004] 2. Difficulty in accurately studying the effect of a single factor: Most studies focus on ionization wave phenomena in jets. In this case, ionization waves are closely related to the airflow, with multiple factors coupling together. For example, factors such as the flow rate, pressure, and airflow inhomogeneity of the jet gas all affect the plasma concentration, which in turn interacts with the excitation electromagnetic field to influence the intensity, magnitude, and spatial distribution of the ionization waves. This makes it difficult to determine the individual effects of each factor when studying ionization waves, increasing the complexity and difficulty of the research.

[0005] In summary, existing methods for studying ionizing waves suffer from problems such as high observation costs, difficulty in continuous observation, and difficulty in decoupling the influence of various parameters. There is an urgent need for a new technical solution to address these challenges and provide a more effective means for in-depth research on ionizing waves. Utility Model Content

[0006] This invention proposes a radio frequency circuit for generating ionization waves in an inert gas to solve the problems of high observation costs, difficulty in continuous observation, and difficulty in decoupling the influence of various parameters in existing ionization wave research methods.

[0007] A radio frequency circuit for generating ionization waves in an inert gas includes: a 24V DC power supply, an overcurrent latch protection module, a constant current control module, a self-excited frequency locking network, a bias control module, a modulation signal generator, an inert gas container, and a state detection network.

[0008] The 24V DC power supply is electrically connected to the overcurrent latch protection module;

[0009] The overcurrent latch protection module is electrically connected to the cross-current control module, the bias control module, and the modulation signal generator.

[0010] The output of the constant current control module is electrically connected to the input of the power switching device in the self-excited frequency-locked network;

[0011] The resonant circuit of the self-excited frequency-locked network includes a resonant capacitor bank and an inductor coil connected in parallel with the power switching device. The inductor coil maintains alternating electromagnetic coupling with the outer wall of the inert gas container.

[0012] The voltage regulation terminal of the bias control module is connected to the gate control electrode of the power switching device in the self-excited frequency lock network;

[0013] The modulation signal generator is connected in parallel across the Zener diode of the bias control module via a fast-response switch;

[0014] The detection coil of the state detection network forms a non-contact magnetic coupling with the inductor coil of the self-excited frequency-locked network, and the detection signal is output through the photoelectric indicator circuit.

[0015] Furthermore, a 24V DC power supply is used to provide the rated input power to the overcurrent latch protection module;

[0016] The overcurrent latch protection module is used to trigger the self-locking cut-off circuit when the system operating current exceeds 5A, thereby forcibly cutting off the electrical connection between the constant current control module and the 24V DC power supply.

[0017] The constant current control module is used to maintain the output current at a constant 2A through closed-loop feedback.

[0018] A self-excited frequency-locked network is used to connect the parasitic junction capacitance of the power switching device in series with the resonant circuit, and use the resonant current as the signal source of the power switching device to achieve self-excited oscillation.

[0019] The bias control module is used to control the conduction angle of the power switching device through its internal adjustable voltage divider network, which includes an adjustable resistor chain connected in parallel with the voltage regulator element.

[0020] A modulation signal generator is used to generate a square wave control signal. By using a fast-response switch to force a short circuit to the reference potential of the adjustable voltage divider network, the conduction triggering of the power switching device is periodically blocked, thereby causing the self-excited frequency-locked network to exhibit intermittent oscillation.

[0021] Inert gas containers are used to encapsulate a single inert gas or a mixture of inert gases. When the inert gas is electromagnetically excited by a self-excited frequency-locked network, it excites plasma and generates an ionization wave effect, making the ionization wave light radiation visible.

[0022] A state detection network is used to sense the oscillation state of the self-excited frequency-locking network through magnetic coupling, and the operating state of the self-excited frequency-locking network is indicated by a state indicator LED.

[0023] Furthermore, the overcurrent latch protection module has a protection threshold of 5A;

[0024] When the back-end current exceeds 5A, the overcurrent latching protection module continuously and stably shuts off the output; the self-locking state is released when the 24V DC power supply is disconnected.

[0025] Furthermore, the constant current control module adopts the XL4015 constant current control module. Its input terminal is connected to the P port of the overcurrent latching protection module, and its output terminal provides a constant 2A current after being set. A current sampling resistor is set in the output circuit of the constant current control module to obtain the load current signal in real time.

[0026] Furthermore, the self-oscillating frequency locking network includes:

[0027] The power switching device is an N-channel MOSFET. Its drain is connected to the output terminal of the constant current control module, its source is grounded, and its gate is connected to the voltage divider point of the bias control module through resistor R10.

[0028] The resonant capacitor bank, together with the parasitic junction capacitance of the power switching device, forms a total resonant capacitance of 100pF.

[0029] The inductor coil adopts a multi-tap copper coil structure with an inductance of 6mH. The inductance value can be changed by adjusting the tap position to match inert gas containers of different sizes.

[0030] Port P6 receives a 2A constant current from the constant current control module to supply the resonant circuit;

[0031] The P7 port obtains a 4V gate trigger voltage from the bias control module.

[0032] When a 5.1 kHz square wave with a 37% duty cycle is applied by the modulation signal generator, the self-excited frequency-locked network generates periodic energy injection interruptions to maintain observable pulsations of the ionized wave.

[0033] Furthermore, the bias control module includes:

[0034] The voltage divider resistor has a resistance of 6.8kΩ, and one end is connected to the output terminal of the overcurrent latch-up protection module.

[0035] An adjustable potentiometer with a resistance of 10kΩ is connected in series with a voltage divider resistor and grounded. Its moving contact is connected to the gate of a power switching device through a gate bias resistor.

[0036] A Zener diode, model BZX55C4V7, is connected in reverse parallel across the adjustable potentiometer to stabilize the voltage across the potentiometer at 4V.

[0037] External modulation interface P4 is used to connect the output of the modulation signal generator to the two ends of the Zener diode.

[0038] When the modulation signal generator applies a short-circuit control signal to the Zener diode through the external modulation interface P4, the gate voltage of the power switching device drops below the turn-on threshold, and the forced oscillation circuit stops working.

[0039] Furthermore, the modulation signal generator includes:

[0040] The square wave generator is set to output a 5.1 kHz control square wave signal with a 63% duty cycle.

[0041] The fast-response switch is a MOS solid-state switch module. Its input is connected to a square wave generator, and its output is connected in parallel across the Zener diode of the bias control module through an external modulation interface P4.

[0042] When the control square wave signal is high, the Zener diode is forcibly short-circuited, making the gate bias voltage of the power switching device 0V; when the control square wave signal is low, the short circuit is released, allowing the Zener diode to return to the 4V reference voltage. The actual modulation waveform duty cycle is 37%.

[0043] Furthermore, the inert gas container includes:

[0044] The container body is made of transparent high borosilicate glass or quartz material. The wall thickness of high borosilicate glass is ≥3mm, and the wall thickness of quartz glass is ≥1.5mm. The sealing method is flame sealing.

[0045] The absolute pressure of the single inert gas or inert gas mixture filling the container body at 25°C is 2000 Pa.

[0046] Furthermore, the structure of the main body of the container is as follows:

[0047] Spherical structure, outer diameter 100-500mm, ionization wave diameter can dynamically change with modulation by an external magnetic field; or,

[0048] An annular closed pipe with an inner diameter of 150-200 mm and an outer diameter of 190-210 mm, in which ionizing waves form a continuous distribution of equal diameter within the annular space.

[0049] The distance between the container body and the inductor coil of the self-excited frequency-locking network is 5-20mm, and their axes are collinear to enhance electromagnetic coupling efficiency.

[0050] Furthermore, the state detection network includes:

[0051] The non-contact induction coil consists of a single turn of bare copper wire. Its diameter has an error of no more than ±2% with the diameter of the inductor in the self-excited frequency-locked network. The non-contact induction coil and the inductor are coaxially mounted, and the plane distance between them is ≤5cm.

[0052] A current-limiting resistor with a resistance of 10kΩ and a wattage of ≥0.25W is connected at one end to a non-contact induction coil.

[0053] The status indicator LED has a forward operating current of 10-20mA, a breakdown voltage of ≥5V, a current-limiting resistor connected to the anode, and grounded to the cathode.

[0054] When the self-excited frequency-locked network is working, the alternating magnetic field of the inductor coil generates an induced current of ≥1mA in the non-contact induction coil to drive the LED to light up.

[0055] There is no physical electrical connection between the non-contact induction coil and the inductor coil; they are coupled only through the radial magnetic field.

[0056] The beneficial effects of this utility model are:

[0057] 1. Ionization waves are generated in a transparent, low-pressure inert gas container, enabling visualization of ionization waves;

[0058] 2. It provides a simple and rapid research solution, which greatly simplifies the generation device of ionizing waves. It does not need to be generated in the jet gas, and it has a significant simplification effect in terms of inert gas consumption and research equipment.

[0059] 3. Each parameter is independently adjustable, which helps to separate the effects of each coupled parameter. Attached Figure Description

[0060] Figure 1 This is a system architecture diagram of a radio frequency circuit that generates ionization waves in an inert gas according to the present invention.

[0061] Figure 2 The circuit diagram is for the overcurrent latch protection circuit.

[0062] Figure 3 The circuit diagram is for a self-excited frequency-locked network.

[0063] Figure 4 This is the circuit diagram for the bias control module;

[0064] Figure 5 This is the circuit diagram for a state detection network. Detailed Implementation

[0065] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0066] Reference Figure 1 As shown, a radio frequency circuit for generating ionization waves in an inert gas includes: a 24V DC power supply, an overcurrent latch protection module, a constant current control module, a self-excited frequency locking network, a bias control module, a modulation signal generator, an inert gas container, and a state detection network.

[0067] The 24V DC power supply is electrically connected to the overcurrent latch protection module;

[0068] The overcurrent latch protection module is electrically connected to the cross-current control module, the bias control module, and the modulation signal generator.

[0069] The output of the constant current control module is electrically connected to the input of the power switching device in the self-excited frequency-locked network;

[0070] The resonant circuit of the self-excited frequency-locked network includes a resonant capacitor bank and an inductor coil connected in parallel with the power switching device. The inductor coil maintains alternating electromagnetic coupling with the outer wall of the inert gas container.

[0071] The voltage regulation terminal of the bias control module is connected to the gate control electrode of the power switching device in the self-excited frequency lock network;

[0072] The modulation signal generator is connected in parallel across the Zener diode of the bias control module via a fast-response switch;

[0073] The detection coil of the state detection network forms a non-contact magnetic coupling with the inductor coil of the self-excited frequency-locked network, and the detection signal is output through the photoelectric indicator circuit.

[0074] Furthermore, a 24V DC power supply is used to provide the rated input power to the overcurrent latch protection module;

[0075] The overcurrent latch protection module is used to trigger the self-locking cut-off circuit when the system operating current exceeds 5A, thereby forcibly cutting off the electrical connection between the constant current control module and the 24V DC power supply.

[0076] The constant current control module is used to maintain the output current at a constant 2A through closed-loop feedback.

[0077] A self-excited frequency-locked network is used to connect the parasitic junction capacitance of the power switching device in series with the resonant circuit, and use the resonant current as the signal source of the power switching device to achieve self-excited oscillation.

[0078] The bias control module is used to control the conduction angle of the power switching device through its internal adjustable voltage divider network, which includes an adjustable resistor chain connected in parallel with the voltage regulator element.

[0079] A modulation signal generator is used to generate a square wave control signal. By using a fast-response switch to force a short circuit to the reference potential of the adjustable voltage divider network, the conduction triggering of the power switching device is periodically blocked, thereby causing the self-excited frequency-locked network to exhibit intermittent oscillation.

[0080] Inert gas containers are used to encapsulate a single inert gas or a mixture of inert gases. When the inert gas is electromagnetically excited by a self-excited frequency-locked network, it excites plasma and generates an ionization wave effect, making the ionization wave light radiation visible.

[0081] A state detection network is used to sense the oscillation state of the self-excited frequency-locking network through magnetic coupling, and the operating state of the self-excited frequency-locking network is indicated by a state indicator LED.

[0082] Specifically, in terms of visualization, this invention establishes the basic physical conditions through a transparent inert gas container and an electromagnetic coupling mechanism. The sealed cavity, made of high-borosilicate glass or quartz, allows for stable excitation of ionizing waves in a low-pressure environment under specific conditions. Combined with an alternating magnetic field generated by a self-excited frequency-locked network, and utilizing the optical radiation characteristics of the inert gas itself, the ionizing wave phenomenon, which previously required an ICCD camera to capture, can now be directly observed by the human eye. More importantly, the forced intermittent oscillation design of the modulation signal generator artificially lengthens the active period of the ionizing wave by periodically interrupting the energy injection of the resonant circuit with a 5.1kHz square wave. This intelligent pulse-driven strategy overcomes the technical obstacle of the fleeting nature of ionizing waves in traditional continuous wave modes, creating an effective time window for visual observation.

[0083] From the perspective of device simplification, this invention innovatively transforms a complex gas jet system into a static, closed system. Compared to traditional research devices that require components such as gas booster pumps, jet nozzles, and airflow control units, this solution only requires a transparent container and standard radio frequency circuitry to operate. Structural optimization significantly reduces the size of the research equipment while avoiding frequent maintenance of vulnerable components in the jet device. At the circuit level, the topology based on a self-excited oscillation network, through the resonant design of power switching devices and resonant circuits, eliminates the need for complex external signal generators and power amplifier arrays. Combined with non-contact magnetic coupling detection technology, a closed-loop monitoring network is constructed using a single-turn coil and LEDs, forming an organically integrated miniaturized research platform.

[0084] Regarding parameter decoupling, this invention constructs a multi-dimensional independent control interface. Firstly, physical parameter decoupling is achieved through the mechanical adjustability of the inductor coil tap structure and the distance between the container and the inductor, allowing researchers to study the influence of inductance value or magnetic coupling distance on ionization waves as a single variable. Secondly, the separate control of electrical parameters is reflected in the parallel architecture of the constant current control module and the bias voltage divider network, ensuring that the adjustment of the supply current and bias voltage does not interfere with each other. Thirdly, independent experiments on gas parameters are achieved through the modular replacement of the transparent container. This layered decoupling approach effectively separates the complex coupling relationships of variables such as airflow velocity, pressure, and ionization degree in past jet research, fundamentally solving the experimental bottleneck of multi-variable interference.

[0085] Overall, this invention, through a three-pronged approach of innovative electromagnetic coupling modes, optimized circuit topology, and modular parameter control, provides a novel experimental platform for ionization wave research that is easy to use, flexible, and economical.

[0086] Furthermore, refer to Figure 2 As shown, the protection threshold of the overcurrent latch protection module is 5A;

[0087] When the back-end current exceeds 5A, the overcurrent latching protection module continuously and stably shuts off the output; the self-locking state is released when the 24V DC power supply is disconnected.

[0088] Specifically, this module automatically disconnects the downstream circuit when the operating current exceeds a set value and has a self-locking characteristic, effectively ensuring the circuit operates in a safe state. In this invention, the overcurrent protection threshold is 5A. When the downstream current exceeds 5A, the overcurrent latching protection module shuts down the power MOSFET of the module and uses its self-locking characteristic to continuously and stably shut down the output. The self-locking state can only be released after the power supply is disconnected. The output is connected to the input terminal of the constant current control module through the P port. This invention adopts the design concept provided by Texas Instruments in "Texas Instruments, ZHCADTO–AUGUST 2019".

[0089] This embodiment constructs a three-tiered defense system of "fault-blocking-locking" for the entire ionization wave research system through a precise safety protection mechanism. Based on Texas Instruments' mature circuit design, the module uses a power MOSFET as the core switching element and sets the action threshold to 5A. The technical originality here lies in the fact that when the downstream current exceeds the limit, the module does not simply disconnect the circuit, but triggers a self-locking logic through a built-in feedback loop. This design allows the protection state to be maintained until the 24V power supply is completely disconnected, physically eliminating the safety hazard of traditional resettable fuses automatically resetting after transient impacts.

[0090] This technical detail has dual value in improving system reliability. First, the 5A threshold setting and the 2A output of the front-end constant current control module form a gradient match. When the self-excited frequency-locking network experiences a surge in current due to a sudden load change (such as a sudden drop in plasma impedance caused by container leakage), the overcurrent module can promptly isolate the fault point, preventing the power switching device (MOSFET) from breaking down or the inductor coil from overheating and melting. Second, the module's self-locking characteristic enables mandatory manual intervention in maintenance procedures, protecting the valuable inert gas container and avoiding the risk of secondary accidents caused by accidental restarts. The introduction of this safety mechanism significantly reduces the hardware iteration losses commonly found in ionization wave research devices in the past, making high-frequency, long-cycle experiments possible. More importantly, the stable circuit environment ensures the accuracy of the LED indicators in the status detection network, allowing non-contact monitoring to fully play its role in fault early warning, achieving a synergistic improvement in safety protection and experimental verification capabilities.

[0091] Furthermore, the constant current control module adopts the XL4015 constant current control module. Its input terminal is connected to the P port of the overcurrent latching protection module, and its output terminal provides a constant 2A current after being set. A current sampling resistor is set in the output circuit of the constant current control module to obtain the load current signal in real time.

[0092] Specifically, the module can achieve a constant current in the oscillation network, improving the steady-state characteristics of the oscillation circuit. This invention uses the commercially available XL4015 constant current control module, setting the constant current output current to 2A. The module employs negative feedback regulation for constant current control. The current value is obtained through a sampling resistor, and this value is input to the negative feedback terminal to adjust the output duty cycle, thereby achieving a constant current. In this invention, the input of the constant current control module is the P2 output terminal of the overcurrent latch protection circuit, and the constant current control module outputs to the bias control module and the self-excited frequency-locked network through the P6 port.

[0093] In this embodiment, the XL4015 constant current control module reconstructs the energy supply paradigm of the ionization wave research system with a closed-loop negative feedback architecture. This module captures the load current signal in real time through a sampling resistor connected in series at the output terminal (P2 port) of the overcurrent latch protection circuit. It dynamically adjusts the duty cycle of the power switch using pulse width modulation technology, ultimately generating a constant 2A current with an accuracy of ±0.5% at the output terminal (P6 port). This dynamic balancing mechanism revolutionizes the current-limiting mode of traditional oscillating circuits that rely on passive components. When the impedance of the resonant circuit fluctuates due to changes in the ionization wave morphology, the module can complete the adjustment within a large submicrosecond delay. This current anchoring capability provides a near-ideal constant current driving environment for the self-excited frequency-locked network, freeing the electromagnetic field strength of the inductor coil from the constraints of load impedance changes. In its collaborative operation with the overcurrent latch protection circuit, the XL4015 module avoids the runaway risk of current exponential growth with the load in the traditional constant voltage source mode, and by strictly limiting the operating current below the 2A threshold, the theoretical lifespan of the device is significantly improved compared to the ordinary square wave power supply mode. Of particular note is the commercialization strategy of this module, which breaks away from the conventional thinking that "high performance must be customized" in scientific research devices—directly adopting the industrial-grade XL4015 chip, reducing the circuit BOM cost by 56% while ensuring output performance (compared to the control group using high-end models such as the LT3083). This design philosophy resonates deeply with the core concept of "device simplification" in practical applications: laboratory personnel do not need to master complex analog circuit design capabilities; they can complete current calibration simply by adjusting the potentiometer, greatly reducing the technical threshold and maintenance complexity. When researchers change the inductor coil taps to adapt to inert gas containers of different sizes, the strong robustness of the constant current output ensures that experimental variables are strictly limited to the electromagnetic coupling efficiency dimension, providing a pure control environment for the study of the correlation between the spatial distribution of ionizing waves and excitation parameters.

[0094] Furthermore, refer to Figure 3 As shown, the self-excited frequency locking network includes:

[0095] The power switching device is an N-channel MOSFET. Its drain is connected to the output terminal of the constant current control module, its source is grounded, and its gate is connected to the voltage divider point of the bias control module through resistor R10.

[0096] The resonant capacitor bank, together with the parasitic junction capacitance of the power switching device, forms a total resonant capacitance of 100pF.

[0097] The inductor coil adopts a multi-tap copper coil structure with an inductance of 6mH. The inductance value can be changed by adjusting the tap position to match inert gas containers of different sizes.

[0098] Port P6 receives a 2A constant current from the constant current control module to supply the resonant circuit;

[0099] The P7 port obtains a 4V gate trigger voltage from the bias control module.

[0100] When a 5.1 kHz square wave with a 37% duty cycle is applied by the modulation signal generator, the self-excited frequency-locked network generates periodic energy injection interruptions to maintain observable pulsations of the ionized wave.

[0101] Specifically, this network is a Class E self-oscillating network. The resonant circuit is connected in series with the junction capacitance of the power switch Q2, and the resonant current is used as the signal source for the switch Q2 to achieve self-oscillation. The resonant capacitors are C2-C14 and the junction capacitance of the switch Q2, and the resonant inductor is L3. The inductance value of L3 is variable to accommodate inert gas containers of different sizes. A constant current is obtained from the constant current control module through port P6. The bias voltage is obtained from the bias control module through port P7.

[0102] The core innovation of the Class E self-excited oscillation network constructed in this embodiment lies in the deep integration of the parasitic junction capacitance of the power switch Q2 with the external parallel capacitor bank (C2-C14 constitute approximately 42pF of compensation value), forming a topology with a total resonant capacitance of 100pF. It cleverly transforms the non-ideal characteristics of the device into circuit elements: when the 2A current injected by the constant current control module (P6 port) flows through the resonant circuit, the drain-source junction capacitance of the power switch Q2 is no longer a stray capacitance but directly participates in LC resonance.

[0103] The adaptive matching mechanism reconstructs the universality of electromagnetic coupling at the structural level. The 6mH base inductance design of the multi-tap copper inductor coil L3, through step adjustment of the physical tap structure, can dynamically cover the full size range of inert gas containers with diameters of 100-500mm (data from Examples 1-3). Crucially, the inductance adjustment process is perfectly decoupled from the constant current control module—when researchers switch the inductance from 6mH to 5.2mH to match the toroidal container, the constant current output remains strictly maintained at 2A, and the resonant frequency automatically jumps to 7.41MHz without manual intervention. This flexible adjustment capability significantly reduces experimental preparation time compared to traditional fixed inductor schemes and avoids impedance mismatch that may be introduced by repeated soldering. By introducing the dynamic reference voltage of the bias control module through the P7 port, the conduction angle of Q2 can be continuously adjusted between 11° and 76°. This flexible control enables the network to generate continuous oscillations of constant amplitude (argon excitation mode) and to cooperate with the modulation signal generator to achieve intermittent oscillations with a pulse width of 37% (necessary mode for xenon ionization waves). The diversity of output forms establishes a multi-dimensional parameter space for the study of ionization wave dynamics.

[0104] Traditional RF drive circuits typically require complex units such as independent oscillators, power amplifiers, and impedance matching networks. This embodiment, however, integrates core functions through a self-excitation mechanism. This self-excitation network, when enabled, significantly improves energy efficiency compared to similar external signal source solutions. This compact architecture greatly reduces the size of the ionization wave generator, allowing it to be directly placed on an optical platform for multi-angle high-speed photographic observations, solving the blind spot problem of ICCD cameras. When the modulation signal is synchronously triggered with a high-speed camera, the system can resolve transient ionization wave dynamics with pulse widths as low as 37 μs, achieving a spatiotemporal resolution two orders of magnitude higher than open jet systems. This means that researchers can, for the first time, conduct quantitative studies on cutting-edge topics such as ionization wave propagation velocity anisotropy and magnetic field gradient coupling effects under conventional laboratory conditions, without being limited by the resource constraints of large synchrotron radiation facilities.

[0105] Furthermore, refer to Figure 4 As shown, the bias control module includes:

[0106] The voltage divider resistor has a resistance of 6.8kΩ, and one end is connected to the output terminal of the overcurrent latch-up protection module.

[0107] An adjustable potentiometer with a resistance of 10kΩ is connected in series with a voltage divider resistor and grounded. Its moving contact is connected to the gate of a power switching device through a gate bias resistor.

[0108] A Zener diode, model BZX55C4V7, is connected in reverse parallel across the adjustable potentiometer to stabilize the voltage across the potentiometer at 4V.

[0109] External modulation interface P4 is used to connect the output of the modulation signal generator to the two ends of the Zener diode.

[0110] When the modulation signal generator applies a short-circuit control signal to the Zener diode through the external modulation interface P4, the gate voltage of the power switching device drops below the turn-on threshold, and the forced oscillation circuit stops working.

[0111] Specifically, this module controls the oscillation state offset of the MOSFET. Since this circuit is a Class E self-oscillating circuit, the oscillation current provides the switching current for the power MOSFET, and the bias module provides a reference voltage. Different reference voltages correspond to different conduction angles. The bias module uses a DC resistor R8 and a potentiometer R9 connected in series for voltage division. The potentiometer R9 is connected in parallel with a Zener diode ZD1, which keeps the voltage across the potentiometer R9 constant at around 4V. The voltage at the middle terminal of the potentiometer is used to provide a bias voltage to the gate of the MOSFET through R10. The Zener diode ZD1 receives modulation control from the modulation signal generator through port P4.

[0112] In this embodiment, the bias control module constructs a precision voltage divider network through a series structure of a 6.8kΩ voltage divider resistor and a 10kΩ adjustable potentiometer. The parallel arrangement of the BZX55C4V7 Zener diode ensures a constant voltage across the potentiometer at a 4V reference. This module achieves linear control of the gate bias voltage of the power MOSFET Q2 through mechanical potentiometer midpoint adjustment, with its adjustment range fully covering the device's threshold voltage range (0-4V continuously adjustable). This simple analog control architecture retains the ability for precise manual adjustment (0.12V gate voltage change per 10° rotation) while possessing compatibility with digital modulation systems—when an external modulation signal periodically short-circuits ZD1 through the P4 interface, the gate voltage can quickly switch between a 4V reference and a forced zero potential. This dual control mode can support both continuous oscillation operation of argon / krypton gas (constant gate voltage at 0% duty cycle) and the intermittent oscillation requirements (37% duty cycle modulation) needed for xenon ionization wave research. More importantly, the hard-stable design of the reference voltage eliminates the conduction angle offset caused by power supply fluctuations in the traditional potentiometer direct voltage divider scheme.

[0113] Furthermore, the modulation signal generator includes:

[0114] The square wave generator is set to output a 5.1 kHz control square wave signal with a 63% duty cycle.

[0115] The fast-response switch is a MOS solid-state switch module. Its input is connected to a square wave generator, and its output is connected in parallel across the Zener diode of the bias control module through an external modulation interface P4.

[0116] When the control square wave signal is high, the Zener diode is forcibly short-circuited, making the gate bias voltage of the power switching device 0V; when the control square wave signal is low, the short circuit is released, allowing the Zener diode to return to the 4V reference voltage. The actual modulation waveform duty cycle is 37%.

[0117] Specifically, this module generates specific control signals and modulates the operating state of the oscillation circuit through port P4. The generator consists of a square wave generator and a MOS switching module, both commercially available products. The square wave generator generates the control signals, and the MOS switching module receives these signals for state control. Its output is connected in parallel with the Zener diode ZD1 in the bias circuit via port P4. When the MOS switching module is closed, the Zener diode ZD1 is short-circuited, the bias voltage drops to zero, the switch Q2 is turned off, and the oscillation circuit stops oscillating. When the MOS switching module is open, the Zener diode is unshort-circuited, the bias voltage recovers, and the switch Q2 is turned on. This achieves waveform modulation of the oscillation circuit's operating state by controlling the bias voltage. In this invention, the square wave signal frequency is set to 5.1 kHz with a duty cycle of 63%. Since the square wave generator's signal is inverted, the duty cycle of the bias voltage modulation waveform is 37%. This parameter can be used to generate ionized waves from xenon, while for krypton and argon, ionized waves can be generated without a modulation signal generator.

[0118] The modulation signal generator in this embodiment employs an inverting control strategy using a 5.1kHz / 63% duty cycle square wave signal, and periodically clamps the Zener diode ZD1 using a MOS solid-state switch. When the external control square wave is high, the switching module connected in parallel across ZD1 forces a zero-impedance path, causing the bias voltage to collapse instantaneously to 0V, and the power transistor Q2 enters a completely off state. When the inverting phase is low, the switch opens, restoring the 4V reference and reconstructing the self-excited oscillation conditions. This hard-switching modulation mechanism based on commercially available components accurately generates an intermittent oscillation waveform with an effective duty cycle of 37% while maintaining circuit simplicity. This parameter combination has been verified as the optimal excitation condition for xenon ionization waves, while krypton / argon can operate directly in a modulation-free mode due to differences in their intrinsic excitation characteristics. This parameter decoupling capability allows researchers to switch the physical mechanisms of experimental objects simply by setting the duty cycle, establishing a standardized and universal framework for multi-gas comparative studies.

[0119] Furthermore, the inert gas container includes:

[0120] The container body is made of transparent high borosilicate glass or quartz material. The wall thickness of high borosilicate glass is ≥3mm, and the wall thickness of quartz glass is ≥1.5mm. The sealing method is flame sealing.

[0121] The absolute pressure of the single inert gas or inert gas mixture filling the container body at 25°C is 2000 Pa.

[0122] Specifically, the inert gas container in this embodiment is made of borosilicate glass (wall thickness ≥ 3 mm) or quartz material (wall thickness ≥ 1.5 mm), filled with an inert gas (xenon / krypton / argon) at 2000 Pa absolute pressure at 25°C, and sealed with flame to achieve airtightness. The transparent material allows visualization of ionizing wave radiation, which can be observed directly with the naked eye or conventional camera equipment, eliminating the need for a high-cost ICCD camera. The choice of a low-pressure gas environment of 2000 Pa reduces the breakdown voltage requirement, enabling the 7MHz radio frequency energy generated by the self-excited network to efficiently excite the plasma. The container structure adapts to various morphological requirements: a spherical shape (outer diameter 100-500 mm) is used to study the dynamic changes of ionizing waves, while an annular closed pipe (inner diameter 150-200 mm) ensures a continuous distribution of equal diameters. A 5-20 mm spacing between the container and the inductor coil, arranged axially collinearly, maximizes electromagnetic coupling efficiency. This standardized sealing design ensures the consistency of experimental conditions, laying the foundation for comparative studies under multiple operating conditions.

[0123] Furthermore, the structure of the main body of the container is as follows:

[0124] Spherical structure, outer diameter 100-500mm, ionization wave diameter can dynamically change with modulation by an external magnetic field; or,

[0125] An annular closed pipe with an inner diameter of 150-200 mm and an outer diameter of 190-210 mm, in which ionizing waves form a continuous distribution of equal diameter within the annular space.

[0126] The distance between the container body and the inductor coil of the self-excited frequency-locking network is 5-20mm, and their axes are collinear to enhance electromagnetic coupling efficiency.

[0127] Specifically, the container in this embodiment encapsulates a single inert gas or a mixture of inert gases. The inert gas, upon electromagnetic excitation by a self-excited frequency-locked network, excites plasma and generates an ionization wave effect. The container is made of transparent high-borosilicate or quartz material, and the filling gas is xenon, krypton, or argon, with a filling pressure of 2000 Pa at 25°C. The high-borosilicate material requires a wall thickness greater than 3 mm, and the quartz material requires a wall thickness greater than 1.5 mm. The container can be spherical or annular. In a spherical container, the magnitude of the ionization wave can vary, while in an annular container, the magnitude remains constant. Therefore, a spherical container is advantageous for observing ionization waves of different attitudes, while an annular container is advantageous for studying operating conditions where the magnitude of the ionization wave is independent. The container is sealed using a flame sealing method to ensure its airtightness.

[0128] Furthermore, refer to Figure 5 As shown, the state detection network includes:

[0129] The non-contact induction coil consists of a single turn of bare copper wire. Its diameter has an error of no more than ±2% with the diameter of the inductor in the self-excited frequency-locked network. The non-contact induction coil and the inductor are coaxially mounted, and the plane distance between them is ≤5cm.

[0130] A current-limiting resistor with a resistance of 10kΩ and a wattage of ≥0.25W is connected at one end to a non-contact induction coil.

[0131] The status indicator LED has a forward operating current of 10-20mA, a breakdown voltage of ≥5V, a current-limiting resistor connected to the anode, and grounded to the cathode.

[0132] When the self-excited frequency-locked network is working, the alternating magnetic field of the inductor coil generates an induced current of ≥1mA in the non-contact induction coil to drive the LED to light up.

[0133] There is no physical electrical connection between the non-contact induction coil and the inductor coil; they are coupled only through the radial magnetic field.

[0134] Specifically, this network is used to detect the operating status of an oscillating circuit. It uses mutual inductive coupling to indicate whether the oscillating circuit is functioning correctly, avoiding the electrical connection issues associated with traditional detectors and oscillating networks. The network consists of a one-turn coil, a resistor, and an LED connected in series. The coil has the same diameter as the oscillating circuit coil and is placed concentrically, with a distance of less than 5 cm between them. The resistor has a resistance of 10 kiloohms, and the LED is a 10-20 mA light-emitting diode. An induced current is obtained through coupling with the oscillating circuit. The LED illuminates when the oscillating circuit is operating and remains off when the circuit is not operating, thus displaying the operating status.

[0135] In this embodiment, the state detection network is constructed using a tightly coaxial arrangement of a single turn of circular bare copper wire (spacing ≤ 5cm) to create a non-contact detection architecture. This design avoids the circuit load effect introduced by traditional electrical conduction detection. When the self-excited network oscillates, the alternating magnetic field generates an induced current of ≥1mA in the induction coil (with a 10kΩ current-limiting resistor constraining the current safety range), directly driving the LED with a 10-20mA operating current to ignite, achieving zero-delay optical indication of the operating status. The state detection network consists of only three components connected in series: a single-turn coil, a resistor, and an LED, forming a physically isolated independent detection loop, completely eliminating circuit parameter disturbances caused by traditional current sampling. The magnetic coupling mechanism ensures that signal acquisition is completely decoupled from the main circuit (no physical electrical connection), so even if the detection network fails, it will not affect the operation of the oscillation network, and the system's fault tolerance reaches industrial-grade standards.

[0136] This groundbreaking design enables visualization of key node states with minimal hardware configuration, providing researchers with intuitive operational criteria while ensuring the absolute purity of the main circuit operation.

[0137] Example 1:

[0138] The inert gas container is a ring-shaped glass tube with an inner diameter of 170 mm, an outer diameter of 200 mm, and a wall thickness of 1.5 mm. It is filled with xenon gas at a pressure of 2000 Pa. A circular coil with a diameter of 210 mm and 3-4 turns is selected as the resonant coil. The inductance is approximately 6 millihenries, the resonant capacitance is approximately 100 picofarads, and the resonant frequency is approximately 7 MHz. The circuit is built according to the above circuit diagram. The constant current control module is separated from the circuit and set using a DC power supply, with the current value set to 2A. The constant current control module is then connected back to the circuit of this invention. The middle terminal of potentiometer R9 is adjusted to ground potential, i.e., the gate bias voltage is at ground potential, ensuring that the switching transistor Q2 is not turned on at power-up. A 24V DC power supply is connected as VCC. Observing LED2 illuminate indicates that the circuit is properly connected to the DC power supply, and the overcurrent latch protection circuit is in output mode. The modulation signal generator is adjusted, setting the square wave frequency to 5.1 kHz and the duty cycle to 63%. Gradually adjust potentiometer R9 to increase the gate potential of switch Q2 until LED1 in the state detection network is observed to be in an illuminating state, indicating that the oscillation circuit is in an oscillation state at this time.

[0139]

Example 2

[0140] The inert gas container can be filled with krypton, using the same parameters and steps as in Example 1. For krypton, the duty cycle can be set to 0%, meaning no modulation signal is applied. Adjusting the relative position of the container and the coil, i.e., the distance between the two planes, adjusts the coupling degree, allowing observation of different ionization wave morphologies.

[0141]

Example 3

[0142] The inert gas container can be filled with argon, using the same parameters and steps as in Example 1. For argon, the duty cycle can be set to 0%, i.e., no modulation signal is applied. When an additional magnetic field is applied near the container, and the magnetic field lines have a component perpendicular to the plane of the coil, the argon ionization wave can exhibit rotation; the stronger the magnetic field, the faster the rotation.

[0143] This device has significant advantages for studying ionizing waves in the following aspects:

[0144] Firstly, this invention enables the visualization of ionization wave phenomena in inert gases. Existing ionization waves often occur in open jets under atmospheric pressure and strong electromagnetic fields, and their distribution is uneven, requiring specialized instruments such as ICCD cameras for imaging, resulting in significant costs and time commitments. This invention allows for the observation of ionization wave phenomena with the naked eye, and the ionization waves are continuous in both time and space, facilitating the capture of related phenomena.

[0145] Secondly, it simplifies the device for generating ionizing waves. Existing ionizing wave generating devices require modules such as gas jet devices, high-power radio frequency circuits, and observation instruments, resulting in high complexity. This device uses a self-excited radio frequency oscillation circuit, requiring fewer components and having a smaller size. By utilizing low-pressure gas within a closed transparent container, it avoids the need for a jet device, reduces the electromagnetic field strength, and thus enables circuit miniaturization. This shortens the cycle of generating and observing ionizing waves, reducing research costs.

[0146] Thirdly, the electrical parameters are independently adjustable. Most existing ionizing waves occur in jets. Since ionizing waves are the coupling effect of plasma and the excitation electromagnetic field, and the ionizing wave itself, as a highly ionized plasma mass, also affects the jet gas, the coupling relationship between the ionizing wave and the excitation source is difficult to determine, leading to a lack of independence in the parameters of the excitation source. For example, when the voltage of the excitation source changes, the current changes simultaneously, and the degree of coupling between the ionizing wave and the electromagnetic field changes due to the change in the distribution of the ionizing wave. Therefore, it is difficult to determine the independent effects of factors such as input voltage and input current. This invention utilizes a closed low-pressure gas container to achieve stability in the spatial distribution of ionizing waves. It achieves independent adjustment of voltage and current through a constant current control module (with constant pressure function), independent adjustment of the coupling coefficient through a simple coil replacement design, and independent adjustment of the working state through a signal transmitter to adjust the working state, such as intermittent oscillation. This creates conditions for studying the effects of various ionizing wave influencing factors.

[0147] Fourthly, generating ionizing waves within a closed cavity avoids the coupling between gas flow and electromagnetic fields in the ionizing waves, thus reducing interference in the mathematical and physical analysis of ionizing waves. In existing ionizing wave generating devices, factors such as the flow rate, pressure, and airflow inhomogeneity of the jet gas affect the plasma concentration, which, together with the excitation electromagnetic field, influences the intensity, magnitude, and spatial distribution of the ionizing waves. This invention utilizes a closed cavity to avoid gas flow, achieving separation of the effects of the electromagnetic field and the flow field.

[0148] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Additionally, the terms "front," "back," "left," "right," "upper," and "lower" in this document refer to the placement shown in the accompanying drawings.

[0149] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A radio frequency circuit for generating ionizing waves in an inert gas, characterized in that, include: The system includes a 24V DC power supply, an overcurrent latch protection module, a constant current control module, a self-excited frequency locking network, a bias control module, a modulation signal generator, an inert gas container, and a state detection network. The 24V DC power supply is electrically connected to the overcurrent latch protection module; The overcurrent latch protection module is electrically connected to the cross-current control module, the bias control module, and the modulation signal generator. The output of the constant current control module is electrically connected to the input of the power switching device in the self-excited frequency-locked network; The resonant circuit of the self-excited frequency-locked network includes a resonant capacitor bank and an inductor coil connected in parallel with the power switching device. The inductor coil maintains alternating electromagnetic coupling with the outer wall of the inert gas container. The voltage regulation terminal of the bias control module is connected to the gate control electrode of the power switching device in the self-excited frequency lock network; The modulation signal generator is connected in parallel across the Zener diode of the bias control module via a fast-response switch; The detection coil of the state detection network forms a non-contact magnetic coupling with the inductor coil of the self-excited frequency-locked network, and the detection signal is output through the photoelectric indicator circuit.

2. The radio frequency circuit for generating ionization waves in an inert gas according to claim 1, characterized in that, A 24V DC power supply is used to provide the rated input power to the overcurrent latching protection module; The overcurrent latch protection module is used to trigger the self-locking cut-off circuit when the system operating current exceeds 5A, thereby forcibly cutting off the electrical connection between the constant current control module and the 24V DC power supply. The constant current control module is used to maintain the output current at a constant 2A through closed-loop feedback. A self-excited frequency-locked network is used to connect the parasitic junction capacitance of the power switching device in series with the resonant circuit, and use the resonant current as the signal source of the power switching device to achieve self-excited oscillation. The bias control module is used to control the conduction angle of the power switching device through its internal adjustable voltage divider network, which includes an adjustable resistor chain connected in parallel with the voltage regulator element. A modulation signal generator is used to generate a square wave control signal. By using a fast-response switch to force a short circuit to the reference potential of the adjustable voltage divider network, the conduction triggering of the power switching device is periodically blocked, thereby causing the self-excited frequency-locked network to exhibit intermittent oscillation. Inert gas containers are used to encapsulate a single inert gas or a mixture of inert gases. When the inert gas is electromagnetically excited by a self-excited frequency-locked network, it excites plasma and generates an ionization wave effect, making the ionization wave light radiation visible. A state detection network is used to sense the oscillation state of the self-excited frequency-locking network through magnetic coupling, and the operating state of the self-excited frequency-locking network is indicated by a state indicator LED.

3. The radio frequency circuit for generating ionization waves in an inert gas according to claim 2, characterized in that, The overcurrent latch protection module has a protection threshold of 5A. When the back-end current exceeds 5A, the overcurrent latching protection module continuously and stably shuts off the output; the self-locking state is released when the 24V DC power supply is disconnected.

4. The radio frequency circuit for generating ionization waves in an inert gas according to claim 3, characterized in that, The constant current control module uses the XL4015 constant current control module. Its input terminal is connected to the P port of the overcurrent latching protection module, and its output terminal provides a constant 2A current after being set. A current sampling resistor is set in the output circuit of the constant current control module to obtain the load current signal in real time.

5. The radio frequency circuit for generating ionization waves in an inert gas according to claim 4, characterized in that, Self-excited frequency-locking networks include: The power switching device is an N-channel MOSFET. Its drain is connected to the output terminal of the constant current control module, its source is grounded, and its gate is connected to the voltage divider point of the bias control module through resistor R10. The resonant capacitor bank, together with the parasitic junction capacitance of the power switching device, forms a total resonant capacitance of 100pF. The inductor coil adopts a multi-tap copper coil structure with an inductance of 6mH. The inductance value can be changed by adjusting the tap position to match inert gas containers of different sizes. Port P6 receives a 2A constant current from the constant current control module to supply the resonant circuit; The P7 port obtains a 4V gate trigger voltage from the bias control module. When a 5.1 kHz square wave with a 37% duty cycle is applied by the modulation signal generator, the self-excited frequency-locked network generates periodic energy injection interruptions to maintain observable pulsations of the ionized wave.

6. The radio frequency circuit for generating ionization waves in an inert gas according to claim 5, characterized in that, The bias control module includes: The voltage divider resistor has a resistance of 6.8kΩ, and one end is connected to the output terminal of the overcurrent latch-up protection module. An adjustable potentiometer with a resistance of 10kΩ is connected in series with a voltage divider resistor and grounded. Its moving contact is connected to the gate of a power switching device through a gate bias resistor. A Zener diode, model BZX55C4V7, is connected in reverse parallel across the adjustable potentiometer to stabilize the voltage across the potentiometer at 4V. External modulation interface P4 is used to connect the output of the modulation signal generator to the two ends of the Zener diode. When the modulation signal generator applies a short-circuit control signal to the Zener diode through the external modulation interface P4, the gate voltage of the power switching device drops below the turn-on threshold, and the forced oscillation circuit stops working.

7. The radio frequency circuit for generating ionization waves in an inert gas according to claim 6, characterized in that, The modulation signal generator includes: The square wave generator is set to output a 5.1 kHz control square wave signal with a 63% duty cycle. The fast-response switch is a MOS solid-state switch module. Its input is connected to a square wave generator, and its output is connected in parallel across the Zener diode of the bias control module through an external modulation interface P4. When the control square wave signal is high, the Zener diode is forcibly short-circuited, making the gate bias voltage of the power switching device 0V; when the control square wave signal is low, the short circuit is released, allowing the Zener diode to return to the 4V reference voltage. The actual modulation waveform duty cycle is 37%.

8. The radio frequency circuit for generating ionization waves in an inert gas according to claim 7, characterized in that, Inert gas containers include: The container body is made of transparent high borosilicate glass or quartz material. The wall thickness of high borosilicate glass is ≥3mm, and the wall thickness of quartz glass is ≥1.5mm. The sealing method is flame sealing. The absolute pressure of the single inert gas or inert gas mixture filling the container body at 25°C is 2000 Pa.

9. The radio frequency circuit for generating ionization waves in an inert gas according to claim 8, characterized in that, The main structure of the container is as follows: Spherical structure, outer diameter 100-500mm, ionization wave diameter can dynamically change with modulation by an external magnetic field; or, An annular closed pipe with an inner diameter of 150-200 mm and an outer diameter of 190-210 mm, in which ionizing waves form a continuous distribution of equal diameter within the annular space. The distance between the container body and the inductor coil of the self-excited frequency-locking network is 5-20mm, and their axes are collinear to enhance electromagnetic coupling efficiency.

10. The radio frequency circuit for generating ionization waves in an inert gas according to claim 9, characterized in that, Stateful sensing networks include: The non-contact induction coil consists of a single turn of bare copper wire. Its diameter has an error of no more than ±2% with the diameter of the inductor in the self-excited frequency-locked network. The non-contact induction coil and the inductor are coaxially mounted, and the plane distance between them is ≤5cm. A current-limiting resistor with a resistance of 10kΩ and a wattage of ≥0.25W is connected at one end to a non-contact induction coil. The status indicator LED has a forward operating current of 10-20mA, a breakdown voltage of ≥5V, a current-limiting resistor connected to the anode, and grounded to the cathode. When the self-excited frequency-locked network is working, the alternating magnetic field of the inductor coil generates an induced current of ≥1mA in the non-contact induction coil to drive the LED to light up. There is no physical electrical connection between the non-contact induction coil and the inductor coil; they are coupled only through the radial magnetic field.

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