A coaxial pulsed trapezoidal magnetic field regulated plasma jet processing device

Abstract

The application relates to the technical field of plasma, in particular to a processing device for coaxial pulse trapezoidal magnetic field regulated plasma jet, which comprises a gas-liquid control module, a plasma generation module, a pulse trapezoidal magnetic field generation module, a power excitation module, a synchronous controller and a plasma processing module; the pulse trapezoidal magnetic field generation module is connected with the plasma generation module and is used for generating a coaxial pulse trapezoidal magnetic field with adjustable parameters; the radial component of the coaxial pulse trapezoidal magnetic field is perpendicular to the movement direction of charged particles in the plasma jet, the plasma jet is provided with a radial expansion or contraction Lorentz force, and the processing area of the plasma jet is adjusted. The device provided by the application generates a stable, dispersed, gas-temperature-near-room-temperature and adjustable-action-area plasma jet, realizes efficient, accurate and low-energy-consumption processing of a target object, and achieves good processing effect.

Description

Technical Field

[0001] This invention relates to the field of plasma technology, and in particular to a processing device for controlling plasma jets with a coaxial pulsed trapezoidal magnetic field. Background Technology

[0002] Atmospheric pressure cold plasma jets possess advantages such as stable discharge under open atmospheric pressure, good controllability, high electron temperature, and low gas temperature. Based on these significant advantages, plasma jets have been widely applied and developed in the fields of biomedicine, environmental remediation, and materials processing.

[0003] However, current plasma sources often use helium for discharge. Although the plasma produced has advantages such as diffuse discharge, low macroscopic gas temperature, and good stability, it is too expensive, and the concentration of active particles in the plasma jet is relatively low. In addition, plasma jets generated under atmospheric pressure have a small treatment area, which cannot well meet the needs of some large-area material surface treatment applications that require high chemical reactivity.

[0004] Patent CN114845459A surrounds a ring magnet on the outside of the gas output pipe. The resulting magnetic field provides a Lorentz force to the plasma jet in the same direction as the plasma jet's flow direction, thus accelerating the plasma jet's flow velocity and addressing the problem of short plasma jet length in existing systems. However, its plasma jet processing area is not effectively increased, limiting its application. Patent CN103585650B uses helium, neon, and argon as the main discharge gases, with small amounts of highly reactive gases such as nitrogen, oxygen, and water vapor added to further enhance plasma activity. However, the addition of these highly reactive gases can lead to unstable discharge and poor dispersion in the plasma jet. Currently, many researchers have proposed methods for controlling plasma jets with magnetic fields to obtain low-temperature, stable, and dispersed plasma jets, but these methods still face various challenges, such as difficulty in controlling the concentration of active particles and a small jet processing area. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a processing device for controlling plasma jets with a coaxial pulsed trapezoidal magnetic field. Under the action of the coaxial pulsed trapezoidal magnetic field, the plasma jet doped with a small amount of easily ionizable gas discharges more stably and diffusely, the concentration of active particles increases, and the gas temperature remains close to room temperature. The radial component of the coaxial pulsed trapezoidal magnetic field is perpendicular to the direction of motion of charged particles in the plasma, providing the plasma jet with a radial expansion or contraction Lorentz force, which makes the effective area of ​​the plasma jet adjustable, achieving efficient and precise processing of the target object, and achieving a very good processing effect.

[0006] This invention is achieved through the following technical solution:

[0007] A processing device for plasma jet controlled by a coaxial pulsed trapezoidal magnetic field includes a gas-liquid control module, a plasma generation module, a pulsed trapezoidal magnetic field generation module, a power excitation module, a synchronization controller, and a plasma processing module, wherein:

[0008] The gas-liquid control module is used to control the content of various media to generate the required mixed gas or gas-liquid mixture.

[0009] The plasma generating module is connected to the gas-liquid control module, which enables the mixed gas or gas-liquid mixture input into the gas-liquid control module to generate a plasma jet.

[0010] The pulsed trapezoidal magnetic field generating module is connected to the plasma generating module and is used to generate a coaxial pulsed trapezoidal magnetic field with adjustable parameters. The radial component of the coaxial pulsed trapezoidal magnetic field is perpendicular to the motion direction of charged particles in the plasma jet, providing the plasma jet with a radially expanding or contracting Lorentz force to adjust the processing area of ​​the plasma jet.

[0011] The power excitation module includes a high-voltage pulse voltage source and a pulse current source. The high-voltage pulse voltage source is connected to the plasma generation module to provide high-voltage excitation for the plasma generation module. The pulse current source is connected to the pulse trapezoidal magnetic field generation module to provide pulse current excitation for the pulse trapezoidal magnetic field generation module.

[0012] The synchronization controller is connected to the power excitation module, so that the control signal of the high voltage pulse voltage source and the control signal of the pulse current source are triggered synchronously and for the same duration, so as to couple the pulse trapezoidal magnetic field generated by the pulse trapezoidal magnetic field generation module with the plasma jet generated by the plasma generation module.

[0013] The plasma processing module is connected to the plasma generating module and is connected to the gas path of the gas-liquid control module, and is used to process the target object.

[0014] Furthermore, the plasma generation module includes a ring-shaped high-voltage copper electrode, a ring-shaped ground electrode, and a dielectric tube. The upstream end of the dielectric tube is connected to the gas-liquid control module, and the downstream end is connected to the plasma processing module. Both the ring-shaped high-voltage copper electrode and the ring-shaped ground electrode are wound around the dielectric tube. The ring-shaped high-voltage copper electrode is connected to the high-voltage pulse voltage source of the power excitation module, and the ring-shaped ground electrode is grounded through a wire.

[0015] Preferably, the dielectric tube is a quartz glass dielectric tube or a ceramic dielectric tube.

[0016] Furthermore, the trapezoidal magnetic field generating module includes an electromagnetic coil and a magnetic core. The magnetic core is sleeved around the dielectric tube and has a trapezoidal cross-section. The electromagnetic coil is a helical coil wound on the magnetic core. The radial radius of the helical coil varies uniformly while the axial spacing remains constant. The electromagnetic coil is connected to a pulse current source.

[0017] Furthermore, a shielding tube is provided between the annular high-voltage copper electrode, the annular ground electrode, and the magnetic core.

[0018] Furthermore, the gas-liquid control module includes an argon storage tank, a nitrogen and oxygen element gas storage tank, and a storage tank for easily ionized gases or liquids.

[0019] Furthermore, the plasma processing module includes a shield and a lifting platform. The lifting platform is installed below the medium tube, and the shield is located around the lifting platform. The shield includes a cover body and a base plate. The cover body has a plasma jet inlet, an air inlet, and an exhaust outlet. The plasma jet inlet is connected to the outlet of the medium tube, and the air inlet is connected to an argon storage tank and a nitrogen and oxygen element gas storage tank. The base plate is fastened to the bottom of the cover body.

[0020] Preferably, the gas-liquid control module includes an argon storage tank, a nitrogen and oxygen element gas storage tank, and an easily ionized gas storage tank. The first argon branch at the outlet of the argon storage tank is connected to the inlet of the plasma processing module and the inlet of the medium tube via an argon mass flow meter. The easily ionized gas branch at the outlet of the easily ionized gas storage tank is connected to the inlet of the medium tube via an easily ionized gas mass flow meter. The nitrogen and oxygen element gas branch at the outlet of the nitrogen and oxygen element gas storage tank is connected to the inlet of the plasma processing module via a nitrogen and oxygen element gas mass flow meter.

[0021] Preferably, the gas-liquid control module includes an argon storage tank, a nitrogen and oxygen element gas storage tank, and an easily ionizable liquid storage tank. The first argon gas branch at the outlet of the argon storage tank is connected to the inlet of the plasma processing module and the inlet of the medium tube via an argon gas mass flow meter. The second gas branch at the outlet of the argon storage tank is connected to the inlet of the easily ionizable liquid storage tank via an easily ionizable gas mass flow meter. The outlet of the easily ionizable liquid storage tank is connected to the inlet of the medium tube. The nitrogen and oxygen element gas branch at the outlet of the nitrogen and oxygen element gas storage tank is connected to the inlet of the plasma processing module via a nitrogen and oxygen element gas mass flow meter.

[0022] Beneficial effects of the invention:

[0023] 1. This invention generates a coaxial pulsed trapezoidal magnetic field through a pulsed trapezoidal magnetic field generation module to control the plasma jet, which can achieve precise and efficient processing of materials or living organisms. The radial component of the coaxial pulsed trapezoidal magnetic field is perpendicular to the direction of motion of charged particles in the plasma, providing a Lorentz force for radial expansion or contraction of the plasma jet. This Lorentz force will increase or decrease the area of ​​the plasma jet, thereby achieving precise and efficient processing of a designated area of ​​the target object without damaging other areas.

[0024] 2. This invention uses a mixture of argon and a trace amount of easily ionizable gas as the working gas. Under the action of the coaxial pulsed trapezoidal magnetic field generated by the pulsed trapezoidal magnetic field generation module, the Penning ionization reaction between metastable argon and easily ionizable gas molecules effectively reduces the discharge initiation voltage and gas temperature, making the device safer. At the same time, by introducing a small amount of nitrogen- and oxygen-containing gas into the shield of the plasma processing module, the problem of unstable and non-dispersed plasma jet caused by the incorporation of nitrogen- and oxygen-containing gases such as oxygen into the working gas can be avoided, while providing nitrogen and oxygen elements to achieve better processing results.

[0025] 3. This invention utilizes the coupling effect between the coaxial pulsed trapezoidal magnetic field generated by the pulsed trapezoidal magnetic field generation module and the plasma jet generated by the plasma generation module. This enhances various chemical reactions between gas molecules, such as Penning ionization, adsorption, and dissociation, further reducing the discharge initiation voltage and gas temperature, and increasing the concentration of highly chemically active particles. Through experiments on the surface modification of polyimide films and the inactivation of methicillin-resistant Staphylococcus aureus, it is shown that the plasma jet enhanced by the trapezoidal magnetic field has a larger treatment area, better modification effect, and better sterilization effect.

[0026] 4. The pulse trapezoidal magnetic field generating module of this invention generates a coaxially symmetrical pulse trapezoidal magnetic field coupled with a plasma jet. In particular, the pulse trapezoidal magnetic field and the plasma jet are triggered synchronously and have the same duration, which can significantly reduce the temperature and energy loss of the pulse trapezoidal magnetic field electromagnetic coil. It is suitable for large-scale industrial applications and shows good application prospects in the fields of material surface treatment and medical sterilization. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0028] Figure 2 This is a schematic diagram of a preferred embodiment of the gas-liquid control module of the present invention.

[0029] Figure 3 This is a schematic diagram of a preferred embodiment of the gas-liquid control module of the present invention.

[0030] Figure 4This is a schematic diagram of the assembly structure of the plasma generation module, the pulsed trapezoidal magnetic field generation module, and the plasma processing module of the present invention.

[0031] Figure 5 This is a schematic diagram of the results of Experiment 1 of the present invention.

[0032] Figure 6 This is a schematic diagram of the results of Experiment 2 of the present invention.

[0033] Figure 7 This is a schematic diagram of the results of Experiment 3 of the present invention.

[0034] In the diagram: 1. Gas-liquid control module; 2. Argon storage tank; 3. Easily ionizable gas storage tank; 4. Nitrogen and oxygen element gas storage tank; 5. Easily ionizable liquid storage tank; 6. Argon mass flow meter; 7. Easily ionizable gas mass flow meter; 8. Nitrogen and oxygen element gas mass flow meter; 9. Plasma generation module; 10. High-voltage pulse voltage source; 11. Synchronization controller; 12. Pulse current source; 13. Pulse trapezoidal magnetic field generation module; 14. Plasma processing module; 15. Dielectric tube; 16. Shielding tube; 17. Ring-shaped high-voltage copper electrode; 18. Magnetic core; 19. Electromagnetic coil; 20. Ring-shaped ground electrode; 21. Cover; 22. Air inlet; 23. Exhaust port; 24. Base plate; 25. Plasma jet inlet. Detailed Implementation

[0035] A processing device for controlling plasma jets with a coaxial pulsed trapezoidal magnetic field is shown in the schematic diagram below. Figure 1 As shown, it includes a gas-liquid control module 1, a plasma generation module 9, a pulsed trapezoidal magnetic field generation module 13, a power excitation module, a synchronization controller 11, and a plasma processing module 14, wherein:

[0036] The gas-liquid control module is used to control the content of various gases or the content of gases introduced into the liquid to generate the required mixed gas or gas-liquid mixture.

[0037] The required mixed gas or gas-liquid mixture can be introduced into the plasma generation module. Under the action of the plasma generation module, a plasma jet with an adjustable working area is generated. Various required gases can also be introduced into the plasma processing module separately, which is beneficial for venting the air in the shield of the plasma processing module. It can also avoid the problem of unstable and non-dispersed plasma jet caused by introducing nitrogen-containing gases such as oxygen into the plasma generation module, and can also provide nitrogen and oxygen elements to achieve better processing results.

[0038] Specifically, the gas-liquid control module can be equipped with an argon storage tank 2, a nitrogen and oxygen element gas storage tank 4, an easily ionizable gas storage tank 3, or an easily ionizable liquid storage tank 5. The storage tanks are used to hold the corresponding liquids or gases. The easily ionizable gases or liquids here can be one or a mixture of methanol, ethanol, and ammonia.

[0039] As a preferred embodiment, such as Figure 2 As shown, Figure 2 The diagram does not include the nitrogen and oxygen gas storage tanks and their connection diagrams; however, the connection diagrams can be found in [reference needed]. Figure 1 , Figure 2 Execution. In this embodiment, the gas-liquid control module includes an argon storage tank, a nitrogen and oxygen element gas storage tank, and an easily ionized gas storage tank. The first argon branch at the outlet of the argon storage tank is connected to the inlet of the plasma processing module and the inlet of the medium tube via an argon mass flow meter 6. The easily ionized gas branch at the outlet of the easily ionized gas storage tank is connected to the inlet of the medium tube via an easily ionized gas mass flow meter 7. The nitrogen and oxygen element gas branch at the outlet of the nitrogen and oxygen element gas storage tank is connected to the inlet of the plasma processing module via a nitrogen and oxygen element gas mass flow meter 8. This allows for effective automatic control of the input amounts of various gases, facilitating the generation of the desired plasma jet. Furthermore, it allows for precise control of the amounts of argon and nitrogen and oxygen element gases entering the plasma processing module, resulting in better processing of the target object.

[0040] As a preferred embodiment two, such as Figure 3 As shown, Figure 3 The document also does not provide a diagram of the nitrogen and oxygen gas storage tanks and their connections; however, the connection diagram can be found in [reference needed]. Figure 1 , Figure 2 Execution. In this embodiment, the gas-liquid control module includes an argon storage tank, a nitrogen and oxygen element gas storage tank, and an easily ionizable liquid storage tank. The first argon gas branch at the outlet of the argon storage tank is connected to the inlet of the plasma processing module and the inlet of the medium tube via an argon mass flow meter. The second gas branch at the outlet of the argon storage tank is connected to the inlet of the easily ionizable liquid storage tank via an easily ionizable gas mass flow meter. The outlet of the easily ionizable liquid storage tank is connected to the inlet of the medium tube. The nitrogen and oxygen element gas branch at the outlet of the nitrogen and oxygen element gas storage tank is connected to the inlet of the plasma processing module via a nitrogen and oxygen element gas mass flow meter. This configuration not only allows for effective automatic control of the input quantities of various gases or liquids, but also better control of the content of easily ionizable substances in the mixed gas, resulting in a better treatment effect for the plasma jet. Furthermore, it allows for precise control of the amount of argon and nitrogen and oxygen element gases entering the plasma processing module, further enhancing the treatment effect on the target object.

[0041] The plasma generating module is connected to the gas-liquid control module, enabling the mixed gas or gas-liquid mixture input to the gas-liquid control module to generate a stable, diffused plasma jet with a gas temperature close to room temperature and an adjustable effective area. After the mixed gas from the gas-liquid control module is input to the plasma generating module, the plasma generating module can apply an electric field to the mixed gas, reduce the initial discharge voltage and the temperature of the mixed gas through Penning ionization, and thus generate a stable, diffused plasma jet with a gas temperature close to room temperature and an adjustable effective area.

[0042] Specifically, the plasma generation module may include a ring-shaped high-voltage copper electrode 17, a ring-shaped ground electrode 20, and a dielectric tube 15. The upstream end of the dielectric tube is connected to the gas-liquid control module, and the downstream end is connected to the plasma processing module. Both the ring-shaped high-voltage copper electrode and the ring-shaped ground electrode are wound around the dielectric tube. The ring-shaped high-voltage copper electrode is connected to the high-voltage pulse voltage source of the power excitation module, and the ring-shaped ground electrode is grounded through a wire. The high-voltage pulse voltage source connection of the plasma generation module can generate an electric field, which reduces the initial discharge voltage and the temperature of the mixed gas through Penning ionization, thereby generating a stable, diffuse plasma jet with a gas temperature close to room temperature and an adjustable effective area. The area of ​​the plasma jet can be adjusted by cooperating with the pulse trapezoidal magnetic field generation module, which can achieve a good processing effect on the target object. The dielectric tube can preferably be a quartz glass dielectric tube or a ceramic dielectric tube, which can provide a good insulation effect.

[0043] Furthermore, a shielding tube 16 can be provided between the annular high-voltage copper electrode, the annular ground electrode and the magnetic core to shield the electromagnetic interference from affecting the annular high-voltage copper electrode and the annular ground electrode.

[0044] The pulsed trapezoidal magnetic field generating module is connected to the plasma generating module and is used to generate a coaxial pulsed trapezoidal magnetic field with adjustable parameters. The radial component of the coaxial pulsed trapezoidal magnetic field is perpendicular to the motion direction of charged particles in the plasma jet, providing a radial expansion or contraction Lorentz force for the plasma jet, adjusting the processing area of ​​the plasma jet. The processing area of ​​the plasma jet can be freely adjusted, thereby achieving efficient and precise processing of the target object.

[0045] Specifically, the trapezoidal magnetic field generating module includes an electromagnetic coil 19 and a magnetic core 18. The magnetic core is sleeved around the dielectric tube and has a trapezoidal cross-section. The electromagnetic coil is a helical coil wound on the magnetic core. The radial radius of the helical coil varies uniformly while the axial spacing remains constant. The electromagnetic coil is connected to a pulsed current source. The trapezoidal cross-section of the magnetic core makes the cross-section of the electromagnetic coil wound on the magnetic core also trapezoidal. Furthermore, the uniform variation in radial radius and constant axial spacing of the helical coil allow for the generation of a coaxial pulsed trapezoidal magnetic field when a pulsed current source inputs a pulsed current to the electromagnetic coil. The radial component of this coaxial pulsed trapezoidal magnetic field is perpendicular to the direction of motion of charged particles in the plasma jet. This provides a Lorentz force for radial expansion or contraction of the plasma jet, increasing or decreasing the plasma jet area, thereby achieving precise and efficient processing of a designated area of ​​the target object.

[0046] The plasma processing module is connected to the plasma generating module and is in gas communication with the gas-liquid control module, and is used to process the target object.

[0047] Preferably, the plasma processing module includes a shield and a lifting platform (not shown). The lifting platform is installed below the medium tube, and the shield is located around the lifting platform. The shield includes a cover body 21 and a base plate 24. The cover body has a plasma jet inlet 25, an air inlet 22, and an exhaust port 23. The plasma jet inlet is connected to the outlet of the medium tube, and the air inlet is connected to an argon storage tank and a nitrogen and oxygen element gas storage tank. The base plate is fastened to the bottom of the cover body.

[0048] When the processing device needs to operate, the base plate can be removed, the lifting platform lowers, the target object is placed on the lifting platform, and then the lifting platform rises to the set position. The base plate is then fastened in place, and the shielding cover is connected to the dielectric tube of the plasma generation module. The plasma jet generated by the plasma generation module enters the shielding cover, effectively isolating it from external air and shielding it from the influence of external air on the plasma jet. The air inlet is connected to the gas-liquid control module. First, the gas-liquid control module generates pure argon gas and introduces it into the shielding cover to expel the air inside. Then, the gas-liquid control module generates a small amount of nitrogen and oxygen element gas and introduces it into the shielding cover. This avoids the instability and lack of dispersion of the plasma jet caused by the introduction of nitrogen and oxygen element gases into the plasma processing module, while also providing nitrogen and oxygen elements for better processing results. All gases are discharged through the exhaust port. The shielding cover can be made of quartz glass to increase the insulation and shielding effect, and the base plate can be made of silicone to increase the sealing effect of the shielding cover.

[0049] The specific assembly structure diagrams of the plasma generation module, pulsed trapezoidal magnetic field generation module, and plasma processing module are as follows: Figure 4 As shown, Figure 4The lifting platform of the plasma processing module is not shown in the image.

[0050] The power excitation module includes a high-voltage pulse voltage source 10 and a pulse current source 12. The high-voltage pulse voltage source can be connected to the annular high-voltage copper electrode of the plasma generation module via wires and a high-voltage pulse power connector. When the mixed gas generated by the gas-liquid control module is introduced into the dielectric tube, it provides high-voltage excitation to the mixed gas, generating a cold plasma jet. The pulse current source can be connected to the pulse trapezoidal magnetic field generation module via wires, providing pulse current excitation to the pulse trapezoidal magnetic field generation module, generating a coaxial pulse trapezoidal magnetic field. The radial component of the coaxial pulse trapezoidal magnetic field is perpendicular to the direction of motion of charged particles in the plasma jet, providing a Lorentz force for radial expansion or contraction of the plasma jet, increasing or decreasing the plasma jet area, thereby achieving precise and efficient processing of a designated area of ​​the target object.

[0051] The synchronization controller is connected to the power excitation module, so that the control signal of the high voltage pulse voltage source and the control signal of the pulse current source are triggered synchronously and for the same duration, so that the pulse trapezoidal magnetic field generated by the pulse trapezoidal magnetic field generating module is coupled with the plasma jet generated by the plasma generating module. This can significantly reduce the temperature and energy loss of the electromagnetic coil of the pulse trapezoidal magnetic field generating module.

[0052] The coaxial pulsed trapezoidal magnetic field precisely controlled plasma jet processing device provided by this invention can process target objects in the following manner:

[0053] S1: Place the target object on the lifting platform. First, control the gas-liquid control module to generate pure argon gas and introduce it into the shielding cover to expel the air in the shielding cover.

[0054] S2: Under the control of various gas mass flow meters, the gas-liquid control module generates a mixed gas containing a specific proportion of argon and trace amounts of easily ionized gas, which is then transmitted to the dielectric tube of the plasma generation module. At the same time, trace amounts of nitrogen and oxygen gas are introduced into the shielding cover.

[0055] S3: The high-voltage pulse voltage source is connected to the ring high-voltage copper electrode through a wire and a high-voltage pulse power connector. The ring ground electrode is grounded through a wire. When the mixed gas generated by the gas-liquid control module is introduced into the dielectric tube, a cold plasma jet is generated under the excitation of the high-voltage pulse voltage source.

[0056] S4: The pulse current source and the high-voltage pulse voltage source are connected through a synchronous controller. The synchronous controller triggers the control signal of the high-voltage pulse voltage source and the control signal of the pulse current source in the same timing sequence. The control signal of the pulse current source is triggered earlier or at the same time as the control signal of the high-voltage pulse voltage source. The pulse width of the control signal of the pulse current source is greater than or the same as the control signal of the high-voltage pulse voltage source. This allows the coaxial pulse trapezoidal magnetic field and the plasma jet to be triggered synchronously and maintained for the same time, thereby greatly increasing the plasma jet processing area.

[0057] S5: The plasma jet, enhanced by the trapezoidal magnetic field, processes the target object in the plasma processing module.

[0058] Specifically, the modification effect of this invention can be verified through polyimide film surface modification experiments:

[0059] Experiment 1: In this experiment, the rare gas is argon, the easily ionized gas is ethanol, and the active gas is oxygen. The gas-liquid control module generates a mixture of argon, ethanol, and oxygen (Ar + EtOH + O2). The oxygen concentration is 600 ppm. There are three groups: an untreated control group, an Ar + EtOH + O2 plasma jet treatment group, and a trapezoidal magnetic field coupled Ar + EtOH + O2 plasma jet treatment group.

[0060] The experimental results of the surface adhesion modification of the polyimide film in this embodiment are as follows: Figure 5 As shown, after Ar+EtOH+O2 plasma jet treatment, the surface adhesion of polyimide film was improved by 158% compared with the control group; after Ar+EtOH+O2 plasma jet treatment with trapezoidal magnetic field coupling, the surface adhesion of polyimide film was improved by 220% compared with the control group.

[0061] Experiment 2: The discharge parameters of the power excitation module were set as follows: voltage 7kV, frequency 20 kHz, pulse width 25 μs, processing time 15s, and processing distance 5cm. Under these parameters, it can be ensured that the Ar+EtOH plasma jet under the trapezoidal magnetic field reaches the surface of the material being treated. Figure 6The changes in the static water contact angle of the PI surface at the jet center and a distance of 0.75 cm from the center are shown after plasma jet treatment of polyimide (PI) films under different magnetic field intensities. The static water contact angle of the untreated PI surface is approximately 75°, while the water contact angle at the jet center after 15 s of plasma jet treatment is approximately 50°. After 15 s of treatment with a trapezoidal magnetic field of B=0.25T, the surface contact angle is approximately 23°, demonstrating a clear enhancement of the plasma jet modification effect. To test the enhancement effect of the trapezoidal magnetic field on the treated area, the contact angle at a distance of 0.75 cm from the jet treatment center was also measured. After treatment with a jet of B=0.00T, the water contact angle was 60°, while after treatment with a trapezoidal magnetic field of B=0.25T, the surface contact angle was approximately 33°, indicating a 38% enhancement in material wettability at the jet edge. The results show that plasma jet treatment enhanced by the trapezoidal magnetic field has a better effect and a larger treated area, showing promising application prospects in the field of material surface modification.

[0062] Experiment 3 verified the sterilization effect through an inactivation experiment against methicillin-resistant Staphylococcus aureus (MRSA). The experiment consisted of three groups: an untreated control group, an Ar+EtOH+O2 plasma jet treatment group, and a trapezoidal magnetic field-coupled Ar+EtOH+O2 plasma jet treatment group. The ethanol gas concentration was 2000 ppm, the oxygen concentration was 800 ppm, and the total gas flow rate was 5 L / min. The plasma generated by discharging these four different working gases was then used to test the concentration of... The suspension of methicillin-resistant Staphylococcus aureus was treated for 5 minutes.

[0063] Experimental results are as follows Figure 7 As shown: Under the same power, the number of methicillin-resistant Staphylococcus aureus (MRSA) bacteria surviving under conventional plasma jet treatment is: The sterilization effect was significant. When treated with a trapezoidal magnetic field coupled with plasma jet, the number of methicillin-resistant Staphylococcus aureus (MRSA) bacteria remained below the detection threshold, resulting in a better sterilization effect than ordinary plasma jet treatment. The results indicate that plasma jet treatment enhanced by a coaxial trapezoidal magnetic field is more effective and has promising application prospects in the field of medical sterilization.

[0064] In summary, this invention provides a processing device for controlling plasma jets with a coaxial pulsed trapezoidal magnetic field. Under the action of the coaxial pulsed trapezoidal magnetic field, the plasma jet doped with a small amount of easily ionizable gas discharges more stably and diffusely, the concentration of active particles increases, and the gas temperature remains close to room temperature. The radial component of the coaxial pulsed trapezoidal magnetic field is perpendicular to the direction of motion of charged particles in the plasma, providing the plasma jet with a Lorentz force that expands or contracts radially, making the effective area of ​​the plasma jet adjustable, achieving efficient and precise processing of the target object, and achieving excellent processing results.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A processing device for controlling plasma jets with a coaxial pulsed trapezoidal magnetic field, characterized in that: It includes a gas-liquid control module, a plasma generation module, a pulsed trapezoidal magnetic field generation module, a power excitation module, a synchronization controller, and a plasma processing module, wherein: The gas-liquid control module is used to control the content of various media to generate the required mixed gas or gas-liquid mixture. The plasma generating module is connected to the gas-liquid control module, enabling the mixed gas or gas-liquid mixture input by the gas-liquid control module to generate a plasma jet. The plasma generating module includes an annular high-voltage copper electrode, an annular ground electrode, and a dielectric tube. The upstream end of the dielectric tube is connected to the gas-liquid control module, and the downstream end is connected to the plasma processing module. The annular high-voltage copper electrode and the annular ground electrode are both wound on the dielectric tube. The annular high-voltage copper electrode is connected to the high-voltage pulse voltage source of the power excitation module, and the annular ground electrode is grounded through a wire. The pulsed trapezoidal magnetic field generating module is connected to the plasma generating module and is used to generate a coaxial pulsed trapezoidal magnetic field with adjustable parameters. The radial component of the coaxial pulsed trapezoidal magnetic field is perpendicular to the direction of motion of charged particles in the plasma jet, providing a Lorentz force for radial expansion or contraction of the plasma jet and adjusting the processing area of ​​the plasma jet. The trapezoidal magnetic field generating module includes an electromagnetic coil and a magnetic core. The magnetic core is sleeved around the dielectric tube and has a trapezoidal cross-section. The electromagnetic coil is a helical coil wound on the magnetic core. The radial radius of the helical coil varies uniformly and the axial spacing remains constant. The electromagnetic coil is connected to a pulsed current source. The power excitation module includes a high-voltage pulse voltage source and a pulse current source. The high-voltage pulse voltage source is connected to the plasma generation module to provide high-voltage excitation for the plasma generation module. The pulse current source is connected to the pulse trapezoidal magnetic field generation module to provide pulse current excitation for the pulse trapezoidal magnetic field generation module. The synchronization controller is connected to the power excitation module, so that the control signal of the high voltage pulse voltage source and the control signal of the pulse current source are triggered synchronously and for the same duration, so as to couple the pulse trapezoidal magnetic field generated by the pulse trapezoidal magnetic field generation module with the plasma jet generated by the plasma generation module. The plasma processing module is connected to the plasma generating module and is connected to the gas path of the gas-liquid control module, and is used to process the target object.

2. The processing device for coaxial pulsed trapezoidal magnetic field-controlled plasma jet according to claim 1, characterized in that: The dielectric tube is a quartz glass dielectric tube or a ceramic dielectric tube.

3. The processing device for coaxial pulsed trapezoidal magnetic field-controlled plasma jet according to claim 1, characterized in that: A shielding tube is provided between the annular high-voltage copper electrode, the annular ground electrode, and the magnetic core.

4. The processing device for coaxial pulsed trapezoidal magnetic field-controlled plasma jet according to claim 1, characterized in that: The gas-liquid control module includes an argon storage tank, a nitrogen and oxygen element gas storage tank, and a storage tank for easily ionized gases or liquids.

5. The processing device for coaxial pulsed trapezoidal magnetic field-controlled plasma jet according to claim 4, characterized in that: The plasma processing module includes a shield and a lifting platform. The lifting platform is installed below the medium tube, and the shield is located around the lifting platform. The shield includes a cover body and a base plate. The cover body has a plasma jet inlet, an air inlet, and an exhaust outlet. The plasma jet inlet is connected to the outlet of the medium tube, and the air inlet is connected to an argon storage tank and a nitrogen and oxygen element gas storage tank. The base plate is fastened to the bottom of the cover body.

6. The processing device for coaxial pulsed trapezoidal magnetic field-controlled plasma jet according to claim 5, characterized in that: The gas-liquid control module includes an argon storage tank, a nitrogen and oxygen element gas storage tank, and an easily ionized gas storage tank. The first argon branch at the outlet of the argon storage tank is connected to the inlet of the plasma processing module and the inlet of the medium tube via an argon mass flow meter. The easily ionized gas branch at the outlet of the easily ionized gas storage tank is connected to the inlet of the medium tube via an easily ionized gas mass flow meter. The nitrogen and oxygen element gas branch at the outlet of the nitrogen and oxygen element gas storage tank is connected to the inlet of the plasma processing module via a nitrogen and oxygen element gas mass flow meter.

7. The processing device for coaxial pulsed trapezoidal magnetic field-controlled plasma jet according to claim 5, characterized in that: The gas-liquid control module includes an argon storage tank, a nitrogen and oxygen element gas storage tank, and an easily ionizable liquid storage tank. The first argon gas branch at the outlet of the argon storage tank is connected to the inlet of the plasma processing module and the inlet of the medium tube via an argon gas mass flow meter. The second gas branch at the outlet of the argon storage tank is connected to the inlet of the easily ionizable liquid storage tank via an easily ionizable gas mass flow meter. The outlet of the easily ionizable liquid storage tank is connected to the inlet of the medium tube. The nitrogen and oxygen element gas branch at the outlet of the nitrogen and oxygen element gas storage tank is connected to the inlet of the plasma processing module via a nitrogen and oxygen element gas mass flow meter.

Images