A high efficiency large volume ecr plasma device

Abstract

The application provides a high-efficiency large-volume ECR plasma device, which comprises a microwave source, a magnetic field coil, a microwave transmission system and an auxiliary system, microwaves generated by the microwave source are fed into a vacuum chamber to generate plasma by the magnetic field coil through the microwave transmission system; the auxiliary system comprises a power supply system, a water cooling system, a detection and protection system, a supporting and moving system and a control system, the power supply system is connected with an external power source, the microwave source and the magnetic field coil, the water cooling system is connected with an external water supply system and the microwave source, the detection and protection system is responsible for detecting the possible sparking phenomenon in the microwave generation and transmission process and can control the shutdown of the microwave source, the supporting and moving system is responsible for adjusting the feeding position and angle, and the control system controls signal acquisition, signal output and microwave feeding angle and position. The ECR plasma device has high energy coupling efficiency, a large plasma generation area and can generate high-density large-volume plasma.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of plasma and microwave, and relates to an ECR plasma source, in particular to a high-efficiency ECR plasma source for generating large volume. BACKGROUND

[0002] The ECR plasma source is powered by a microwave source, and energy is coupled into the plasma in the form of microwaves. The heating mechanism of the ECR plasma source is that when the electrons in the magnetic field and the ECR wave reach the cyclotron resonance condition, the electric field seen by the electrons is stationary, at this time the heating electrons continue to exchange energy with other neutral particles, thereby generating plasma. Therefore, using the ECR wave can generate a large volume of plasma with a relatively low power, and the energy coupling efficiency is also high. The use of ECR requires the cooperation of a magnetic field, microwaves of different frequencies will resonate in regions with different magnetic field sizes, and the magnetic field can constrain the generated plasma to form a relatively stable discharge region. The traditional ECR plasma source has a small discharge volume, a small power, a short service life, and is complicated to operate, which is not conducive to maintenance. SUMMARY

[0003] The purpose of the present application is to provide a high-efficiency ECR plasma device for generating large volume, which uses a solid-state microwave source to provide microwaves, uses an antenna and a waveguide to transmit microwaves to a discharge region, which is convenient to arrange, reliable to operate, low in cost, high in power and adjustable, high in energy coupling efficiency, large in discharge volume, and can generate plasma with a density of 5x10 11 cm -3 in an area with a diameter of several meters.

[0004] The purpose of the present application is achieved by the following technical solutions:

[0005] A high-efficiency ECR plasma device for generating large volume, comprising a microwave source, a magnetic field coil, a microwave transmission system and an auxiliary system, wherein:

[0006] The microwave source is connected to the microwave transmission system, the magnetic field coil is located in the vacuum chamber to provide a magnetic field for it, and the microwave generated by the microwave source is fed into the vacuum chamber through the microwave transmission system to generate plasma in the magnetic field;

[0007] The auxiliary system includes a power supply system, a water cooling system, a detection and protection system, a support and movement system and a control system;

[0008] The power supply system is connected with an external power source, the microwave source and the magnetic field coil to provide power for the ECR plasma device;

[0009] The water cooling system is connected with an external water supply system and the microwave source to supply water cooling for the microwave source;

[0010] The detection protection system is a spark protection device connected at the microwave source, responsible for detecting the spark phenomenon that may occur in the microwave generation and transmission process and can control the shutdown of the microwave source to protect the ECR plasma device;

[0011] The support motion system provides mechanical support for the microwave transmission system and is responsible for adjusting the feed-in position and angle;

[0012] The control system is divided into a microwave source control system and a motor control system, which are connected to the microwave source and the support motion system respectively, and control signal acquisition, signal output and microwave feed-in angle and position.

[0013] Compared with the prior art, the present application has the following advantages:

[0014] 1. The ECR plasma device of the present application uses a solid-state microwave source to provide microwaves, uses an antenna and a waveguide to transmit microwaves, and uses a magnetic field coil to assist energy coupling and confine the plasma.

[0015] 2. The ECR plasma device of the present application is easy to arrange, reliable in operation, low in cost, high in power and adjustable, with a center frequency of 2.45 GHz, and can change the microwave feed-in angle and replace the feed-in window very conveniently.

[0016] 3. The ECR plasma device of the present application has high energy coupling efficiency and a large plasma generation area, and can well generate high-density large-volume plasma required by various experimental devices. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The magnetic field simulated by the comsol software is shown in the figure, and the 0.875T isosurface is the plasma generation area;

[0018] Figure 2 It is the internal physical diagram of the solid-state microwave source;

[0019] Figure 3 It is a photo of the generated plasma taken by a high-speed camera;

[0020] Figure 4 It is a schematic diagram of the overall design of the microwave source;

[0021] Figure 5 It is an antenna photo;

[0022] Figure 6 It is a probe of the spark protection device;

[0023] Figure 7 It is a structural schematic diagram of the high-efficiency large-volume ECR plasma device. DETAILED DESCRIPTION

[0024] The technical solutions of the present application are further described below in conjunction with the drawings, but are not limited thereto, and any modification or equivalent replacement of the technical solutions of the present application without departing from the spirit and scope of the present application shall be covered in the protection scope of the present application.

[0025] The present application provides a high-efficiency large-volume ECR plasma device, such as Figure 7 As shown, the device comprises a microwave source 1, a magnetic field coil 2, a microwave transmission system 3 and an auxiliary system, wherein:

[0026] The microwave source 1 is connected to the microwave transmission system 3, the magnetic field coil 2 is located in the vacuum chamber 4 to provide a magnetic field for it, and the microwave generated by the microwave source 1 is fed into the magnetic field in the vacuum chamber 4 to generate plasma;

[0027] The auxiliary system comprises a power supply system 5, a water cooling system 6, a detection and protection system 7, a support movement system 8 providing a mounting position for the feed-in antenna of the ECR system, and a control system 9, which are necessary components to ensure the safe and normal operation of the ECR plasma source, and are connected to each part to provide control, support, cooling and protection;

[0028] The power supply system 5 is connected to the external power supply and the microwave source 1 and the magnetic field coil 2 to provide power for the system;

[0029] The water cooling system 6 is connected to the external water supply system to provide water cooling for the microwave source 1;

[0030] The detection and protection system 7 is mainly a spark protection device connected to the microwave source 1, which is responsible for detecting the possibility of fire during microwave generation and transmission and can control the shutdown of the microwave source to protect the system;

[0031] The support movement system 8 covers the outside of the vacuum tank body, provides mechanical support for the microwave transmission system 3 and is responsible for adjusting the feed-in position and angle;

[0032] The control system 9 is divided into a microwave source control system and a motor control system, which are connected to the microwave source 1 and the support movement system 8 respectively, and control signal acquisition, signal output and microwave feed-in angle and position respectively.

[0033] In the present application, the microwave source 1 uses a full-solid-state microwave source system (CN116647230A), the internal physical diagram of which is as shown in Figure 2 The overall design is as shown in Figure 4As shown, compared with the traditional vacuum tube amplifier, the system has stable and reliable performance, high frequency stability, convenient output power adjustment, long service life of solid-state semiconductor devices, low cost in the whole life cycle, low operating voltage, easy operation and maintenance, no preheating, instantaneous start-up and many other advantages, and is the core of the ECR system. The microwave source can output a pulse or continuous signal with a power of 10KW, and the power is adjustable. The working frequency is fixed at 2.45GHz, the frequency stability is very good, the working voltage is 32V, the output power is adjustable, and the maximum is 10kW. The phase consistency of the output microwave can be ensured by the control algorithm (CN114883769A). The microwave source 1 is controlled by a single-chip microcomputer and can be remotely controlled. The microwave source 1 is water-cooled and needs to be connected to a power supply system 5 and a water-cooling system 6, which is powered by 220v alternating current. The microwave source 1 has a spark protection device, which is part of the protection system and can be turned off within 30 microseconds when receiving a spark signal.

[0034] In the application, the microwave transmission system 3 is perpendicular to the magnetic field at the microwave feeding position and transmits about 10kW of microwave, which is fed from the DN500 flange window 10 above the top platform of the vacuum chamber 4. The microwave feeding position is connected to the motor control system.

[0035] In the application, the microwave transmission system 3 adopts a rectangular waveguide design, and the electromagnetic wave propagates along the X-axis of the device in the waveguide propagation direction, which is perpendicular to the magnetic field at the feeding position, and the power capacity is greater than 10kW. The system includes several waveguides and feeding antennas (as shown in Figure 5 The system includes a matching electrically remote-controlled distributor, a directional coupler and a spark detection port reserved for the protection system, a directional coupler output end connected to the microwave source and an input end of the feeding antenna, a distributor arranged on the antenna to control the rotation angle of the antenna, a motor fixed on the cavity and a detection window arranged on a bend in the waveguide. The system uses power reflection to realize multiple reflection and absorption in the vacuum tank, and the power loss through the window opposite the installation flange is less than 30%, and the part of the feeding antenna extending into the tank body is not higher than 30mm relative to the inner surface of the tank.

[0036] In the application, the magnetic field in the vacuum chamber 4 is provided by the magnetic field coil 2, which is a multi-turn hollow annular coil or a magnetic core rod-shaped coil connected to the power supply system 5 to generate a magnetic field when energized. It can provide the required magnetic field for energy coupling and provide magnetic confinement for the plasma. The magnetic field is a primary field generated in the space around the multi-turn hollow annular coil or the magnetic core rod-shaped coil when a harmonic or pulsed current is passed through it. The magnetic field coil has a large current and a high magnetic field strength, and can generate a highest plasma density of not less than 10 11 cm -3The high-density plasma has a plasma density repeatability of better than ±5%.

[0037] In the application, the auxiliary system includes various systems for ensuring normal operation of the device, such as a power supply system 5, a water cooling system 6, a supporting movement system 8, a control system 9, and a detection protection system 7. The water cooling system 6 is connected with an external water supply system and can supply water for the cooling system of the microwave source 1. The power supply system 5 is connected with an external power supply system and can supply power for the entire ECR source. The supporting movement system 8 is light in weight and small in coverage area, has four reserved microwave feed-in windows and matched supporting facilities, and can change the microwave injection position to the top of the cavity or a 45° angle position around the cavity by selecting different feed-in windows. The feed-in port in the vacuum tank can be rotated by not less than ±5°, and the microwave injection position can cover a distance of not less than 40 cm from the horizontal center plane of the tank by adjusting the angle. The microwave feed-in system at each window position is completely consistent from the feed-in antenna to the soft waveguide, and the number of transmission line waveguides is kept to a minimum in the design.

[0038] In the application, the control system 9 includes a microwave source control system and a motor control system, wherein the motor control system is used to change the angle position of microwave injection at each window. The control system 9 reserves an interface (network interface / serial communication interface) with a data acquisition and control subsystem of a space plasma environment simulation and research system, can meet the communication protocol requirements of the data acquisition and control subsystem, and can respond to the control of the data acquisition and control subsystem. The control system can control the output power size and output mode of the microwave source, and can also fine-tune the feed-in angle position by controlling the movement motor.

[0039] In the application, the detection protection system 7 includes a spark protection device (such as a spark protection device shown in FIG. Figure 6 The detection protection system 7 can independently detect the spark phenomenon in the microwave transmission system 3, can quickly shut down the microwave source when the experimental device sparks, and can protect the microwave transmission system 3.

[0040] In the application, the microwave source 1 is used to generate high-power microwave; the magnetic field coil 2 can provide the required magnetic field for energy coupling and can provide magnetic confinement for the plasma; the microwave transmission system 3 can feed the high-power microwave generated by the microwave source 1 into the experimental cavity around the magnetic field coil 2. The microwave source 1 is provided with cooling water and power by the external water supply and power supply system, and under the control of the control system 9, can output microwave with a center frequency of 2.45GHz and a power of up to 10Kw. The microwave is fed into the area around the magnetic field through the antenna installed on the experimental cavity via the microwave transmission system 3, and high-density plasma is generated in the area with a magnetic field of 875Gs. The detection protection system 7 of the ECR plasma source can independently detect whether the lightning phenomenon occurs in the microwave transmission system 3, and once the lightning occurs, it will immediately cut off the output of the microwave source 1 to protect the microwave transmission system 3.

[0041] Figure 1 For the magnetic field simulated by the comsol software, the 0.875T isosurface in the figure is the area where the plasma is generated; Figure 3 For the photo of the generated plasma taken by the high-speed camera. Figure 1 And Figure 3 As can be seen, the discharge volume is large, and the radius can reach nearly 2m.

Claims

1. A device for efficiently generating large-volume ECR plasma, characterized in that The ECR plasma device includes a microwave source, a magnetic field coil, a microwave transmission system and an auxiliary system, wherein: The microwave source is connected to a microwave transmission system, and a magnetic field coil is located in the vacuum chamber to provide a magnetic field therefor. The microwaves generated by the microwave source are fed into the magnetic field in the vacuum chamber via the microwave transmission system to generate plasma. The microwave transmission system adopts a rectangular waveguide design, and the electromagnetic wave propagates along the X-axis of the device in the waveguide, which is perpendicular to the magnetic field at the feed point; The auxiliary system includes a power supply system, a water cooling system, a detection and protection system, a support and motion system, and a control system; The power supply system is connected to an external power source, a microwave source and a magnetic field coil to provide power to the ECR plasma device; The water cooling system is connected to the external water supply system and the microwave source to supply water for cooling the microwave source; The detection and protection system is responsible for detecting the sparking phenomenon that may occur during the microwave generation and transmission process and can control and shut down the microwave source to protect the ECR plasma device; The support motion system provides mechanical support for the microwave transmission system and is responsible for adjusting the feeding position and angle; The control system is divided into a microwave source control system and a motor control system, which are respectively connected to the microwave source and the support motion system to control signal acquisition, signal output and microwave feeding angle and position.

2. The device for efficiently generating large-volume ECR plasma according to claim 1, characterized in that The microwave source is an all-solid-state microwave source system.

3. The device for efficiently generating large-volume ECR plasma according to claim 1, characterized in that The microwave transmission system is perpendicular to the magnetic field at the microwave feeding point, and the microwave feeding point is connected to the motor control system.

4. The device for efficiently generating large-volume ECR plasma according to claim 1, characterized in that The magnetic field coil is a multi-turn hollow annular coil or a magnetic core rod coil.

5. The device for efficiently generating large-volume ECR plasma according to claim 1, characterized in that The detection and protection system comprises an ignition protection device arranged at a microwave source and an ignition detection head arranged on a transmission line.

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