Optical fiber trigger pseudo spark switch

Abstract

The invention provides an optical fiber trigger pseudo-spark switch, which comprises a cathode assembly for generating initial electrons; the anode assembly and the cathode assembly are arranged at intervals, and the anode assembly provides an electric field to drive electrons to move; the discharge gap is positioned between the cathode assembly and the anode assembly; the cathode assembly comprises a cathode hole, a cathode cavity for generating a hollow cathode effect and a trigger for providing initial electrons; the trigger comprises an optical fiber structure used for conducting laser into the cathode cavity and a photoelectric cathode covering the cathode hole; the laser emitting end of the optical fiber structure extends into the cathode cavity; the laser emitting end of the optical fiber structure, the photoelectric cathode and the cathode hole are coaxially arranged.

Description

Technical Field

[0001] This invention relates to the field of pulsed power technology. More specifically, it relates to an optical fiber triggered pseudo-spark switch. Background Technology

[0002] With the continuous advancement of pulse power technology, pulse power devices have gradually moved towards the terawatt (TW) level. As a key component for energy compression in pulse devices, the pseudo-spark switch plays a crucial role in the further development of pulse power technology. However, the pseudo-spark switches widely used in the industry still suffer from susceptibility to various interferences. For example, in high-voltage, high-current pulse power devices, pseudo-spark switches are susceptible to electromagnetic interference; simultaneously, they are also easily affected by environmental factors (such as vibration, humidity, and ambient light intensity), causing the switch to malfunction and ultimately leading to device damage. Summary of the Invention

[0003] The purpose of this invention is to provide an optical fiber triggered pseudo-spark switch to solve at least one of the above-mentioned technical problems.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] This invention provides an optical fiber triggered pseudo-spark switch, comprising:

[0006] The cathode assembly generates the initial electrons;

[0007] An anode assembly is spaced apart from the cathode assembly, and the anode assembly provides an electric field to drive electron movement;

[0008] The discharge gap is located between the cathode assembly and the anode assembly;

[0009] The cathode assembly includes a cathode aperture, a cathode cavity that produces a hollow cathode effect, and a trigger for providing initial electrons;

[0010] The trigger includes an optical fiber structure for transmitting laser light into the cathode cavity and a photocathode covering the cathode aperture; the laser emitting end of the optical fiber structure extends into the cathode cavity; the laser emitting end of the optical fiber structure, the photocathode, and the cathode aperture are coaxially arranged.

[0011] In a preferred embodiment, the photocathode includes a mesh portion and a sidewall portion, wherein at least a portion of the edge of the mesh portion is fixed to the side edge of the cathode hole opposite to the anode assembly via the sidewall portion.

[0012] In a preferred embodiment, the photocathode is located inside the cathode cavity.

[0013] A preferred embodiment is that the mesh portion is made of magnesium oxide.

[0014] A preferred embodiment is that the cathode assembly includes a cathode housing with a cathode cavity inside and a cathode baffle disposed inside the cathode housing. The cathode baffle includes a first through hole for laser to pass through. The first through hole is coaxially disposed with the cathode hole. The cathode housing includes an upper end plate with a cathode hole. A first cavity space for generating a hollow cathode effect is formed between the cathode baffle and the upper end plate.

[0015] The cathode housing also includes a lower end plate for assembling and fixing the optical fiber structure, and a second cavity space is formed between the cathode baffle and the lower end plate; the laser emitting end of the optical fiber structure extends into the second cavity space.

[0016] A preferred embodiment is that the optical fiber structure includes a conductive structure, which constitutes the laser emitting end of the optical fiber structure. The conductive structure includes a connecting cylinder fixed to the lower end plate and a collimating lens and a focusing lens fixed inside the connecting cylinder and arranged sequentially along the laser emission direction. The connecting cylinder passes through the lower end plate and extends into the second cavity space. The connecting cylinder is coaxially arranged with the cathode hole.

[0017] In a preferred embodiment, the anode assembly includes an anode housing, an anode cavity is formed inside the anode housing, an anode hole is formed on the anode housing coaxially with the cathode hole, and the anode cavity is connected to the discharge gap through the anode hole;

[0018] The anode cavity includes a first-stage cavity near the cathode assembly for initial discharge and a second-stage cavity away from the cathode assembly for high-current conduction; the first-stage cavity is connected to the discharge gap through an anode hole;

[0019] A metal partition is formed inside the anode housing, and the metal partition includes a second through hole coaxially arranged with the anode hole. The first-stage cavity and the second-stage cavity are connected through the second through hole.

[0020] A preferred embodiment is that the diameter of the second through hole is larger than the diameter of the anode hole.

[0021] In a preferred embodiment, the anode assembly further includes a gas pipe fixed to the anode housing for charging and venting, the gas pipe being connected to the second-stage cavity.

[0022] In a preferred embodiment, both the cathode assembly and the anode assembly include electrodes for connection to an external circuit.

[0023] The beneficial effects of this invention are as follows: This invention provides a fiber-optic triggered pseudo-spark switch comprising a cathode assembly that generates initial electrons; an anode assembly spaced apart from the cathode assembly, the anode assembly providing an electric field to drive electron movement; and a discharge gap located between the cathode assembly and the anode assembly; the cathode assembly includes a cathode aperture, a cathode cavity that generates a hollow cathode effect, and a trigger for providing initial electrons; the trigger includes an optical fiber structure for transmitting laser light into the cathode cavity and a photocathode covering the cathode aperture; the laser emission end of the optical fiber structure extends into the cathode cavity; the laser emission end of the optical fiber structure, the photocathode, and the cathode aperture are coaxially arranged. The above-mentioned fiber-optic triggered pseudo-spark switch has a value greater than 10. 6 The lifespan is several times that of traditional switches. Compared to the electrical triggering method of traditional switches, fiber optic triggering enables remote, non-contact, and precise control of the switch's normal operation. It can truly isolate the low-voltage control circuit from the high-voltage charging and discharging circuit in the whole system, providing a technical basis for the high-potential floating series and parallel application of switches. This invention covers the cathode hole of the cathode assembly with a photocathode, utilizing the low work function of the magnesium oxide mesh structure of the photocathode to stably generate photoelectrons even under conditions of light energy density difference, thereby improving electron generation efficiency and laser utilization, ensuring the normal operation of the pseudo-spark switch. Furthermore, the laser passing through the mesh structure can weakly ionize the hydrogen gas in the discharge gap, which helps the pseudo-spark switch conduct. Attached Figure Description

[0024] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0026] Figure 2 This is a schematic diagram of the cathode assembly of the present invention.

[0027] Figure 3 This is a schematic diagram of the structure of the anode assembly of the present invention.

[0028] Figure 4 and Figure 5 This is a schematic diagram of the structure at the cathode hole of the present invention.

[0029] Figure 6 This is a schematic diagram of the conductive structure of the present invention. Detailed Implementation

[0030] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0031] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0032] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0033] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0035] Space light transmission boasts high beam quality and energy density, but it is susceptible to environmental interference (such as vibration, humidity, and ambient light intensity). In contrast, fiber optic transmission is unaffected by environmental interference; however, due to its larger beam divergence angle, even after collimation, its energy density remains lower than that of space light transmission. This can lead to performance degradation or even failure of the pseudo-spark switch. To address these issues, this invention provides an fiber optic triggered pseudo-spark switch, combining... Figures 1 to 6 As shown, the fiber-optic triggered pseudo-spark switch specifically includes: a cathode assembly 1, which generates initial electrons; an anode assembly 2, spaced apart from the cathode assembly 1, which provides an electric field to drive the electron movement; and a discharge gap 5, located between the cathode assembly 1 and the anode assembly 2. The cathode assembly 1 and the anode assembly 2 are fixed together by an insulating connector 3. The insulating connector 3 is an insulating ceramic cylinder with openings at both ends along its axial direction. The cathode assembly 1 and the anode assembly 2 are inserted into the insulating ceramic cylinder from the openings at both ends and fixed to the insulating ceramic cylinder. Inside the insulating ceramic cylinder, the discharge gap 5 is formed between the cathode assembly 1 and the anode assembly 2.

[0036] Furthermore, the cathode assembly 1 includes a cathode aperture 11, a cathode cavity that generates a hollow cathode effect, and a trigger for providing initial electrons. The trigger includes an optical fiber structure for transmitting laser light into the cathode cavity and a photocathode 13 covering the cathode aperture 11. The laser emitting end of the optical fiber structure extends into the cathode cavity. The laser emitting end of the optical fiber structure, the photocathode 13, and the cathode aperture 11 are coaxially arranged. The cathode aperture 11 communicates with the cathode cavity, and the cathode cavity communicates with the discharge gap 5 through the cathode aperture 11. The optical fiber structure transmits laser light into the cathode cavity, causing the laser to irradiate the surface of the photocathode 13 and generate initial electrons. These initial electrons undergo electron avalanche within the cathode cavity through the hollow cathode effect and, under the traction of the anode field, enter the anode cavity in the form of an electron beam through the cathode aperture 11 and the anode aperture 22, thus achieving the conduction of the pseudo-spark switch. It is understood that... Figure 1 The vertical dashed line in the figure represents the central axis of the pseudo-spark switch of this invention. Through the above design, the electron generation efficiency and laser utilization rate can be improved when using fiber optic transmission, thus ensuring the normal operation of the pseudo-spark switch even when the light energy density is weaker than that of spatial light transmission.

[0037] The pseudo-spark switch of this invention meets the design requirements of pulse power devices to resist strong electromagnetic interference. Furthermore, the fiber-optic triggered pseudo-spark switch of this invention features a mesh-structured magnesium oxide photocathode 13 at the cathode hole 11, utilizing its low work function to stably generate photoelectrons even under conditions of low light energy density. The laser light passing through the photocathode 13 weakly ionizes the hydrogen gas in the discharge gap 5, facilitating the conduction of the pseudo-spark switch, improving electron generation efficiency and laser utilization, and ensuring smooth conduction of the pseudo-spark switch. The cathode assembly 1 is at a negative high voltage relative to the anode assembly 2, causing electrons to move from the cathode assembly to the anode assembly under the influence of the electric field. In the initial discharge stage, the laser light transmitted through the fiber structure irradiates the surface of the photocathode 13. Because the mesh portion of the photocathode 13 is made of magnesium oxide material with low work function, it can stably generate photoelectrons even under low laser energy density. These photoelectrons undergo electron avalanche within the cathode cavity under the effect of the hollow cathode, forming a large number of initial electrons. Under the pull of the anode electric field, these initial electrons pass through the cathode hole 11 and the anode hole 22 in the form of an electron beam and enter the anode cavity, further triggering the discharge of the discharge gap 5 and realizing the smooth conduction of the pseudo-spark switch.

[0038] In one specific embodiment, the photocathode 13 includes a mesh portion 131 and a sidewall portion 132. At least a portion of the edge of the mesh portion 131 is fixed to the side edge of the cathode hole 11 opposite to the anode assembly 2 via the sidewall portion 132. The photocathode 13 is located within the cathode cavity. The mesh portion 131 is made of magnesium oxide. The sidewall portion 132 extends from the edge of the cathode hole 11 into the cathode cavity, and the sidewall portion 132 has a continuous or discontinuous annular structure. The placement of the aforementioned mesh magnesium oxide can prevent it from being ablated during operation, thus improving its service life. The pseudo-spark switch of the present invention is a novel high-power gas discharge switch that combines the advantages of a trigger tube and a thyristor, featuring small size, high withstand voltage, large conduction current, good reliability and stability, and long service life. The working principle of the pseudo-spark switch of this invention is as follows: Laser energy is transmitted through an optical fiber structure and acts on the photocathode 13. The photocathode 13 generates initial electrons required for the pseudo-spark switch to conduct inside the cathode cavity. These initial electrons undergo electron avalanche through the hollow cathode effect and are pumped to the anode under the action of the anode field, thus turning on the pseudo-spark switch. The mesh-like magnesium oxide structure ensures that the generated electrons enter the discharge gap 5 and also allows the laser to weakly ionize the gas in the discharge gap 5, improving the switch discharge time parameters. The mesh portion 131 of the photocathode 13 is specifically a 200-mesh mesh-like magnesium oxide. Magnesium is a low work function metal, and studies have shown that magnesium oxide is more likely to generate photoelectron emission than magnesium. The advantage of using a mesh structure is that, in addition to ensuring that photoelectrons can smoothly enter the withstand voltage gap, it also allows the laser to pass through the discharge gap 5. The laser can weakly ionize the hydrogen gas in the discharge gap 5, and the weakly ionized gas can effectively reduce the ignition delay time of the switch.

[0039] In one specific embodiment, the cathode assembly 1 includes a cathode housing 15 with a cathode cavity formed inside and a cathode baffle 18 disposed within the cathode housing 15. The cathode baffle 18 includes a first through hole 17 for laser light to pass through, and the first through hole 17 is coaxially arranged with the cathode hole 11. The cathode housing 15 includes an upper end plate 152 with the cathode hole 11 formed in the middle, and a first cavity space 12 for generating a hollow cathode effect is formed between the cathode baffle 18 and the upper end plate 152. The cathode housing 15 also includes a lower end plate 153 for assembling and fixing an optical fiber structure, and a second cavity space 16 is formed between the cathode baffle 18 and the lower end plate 153. The laser emitting end of the optical fiber structure extends into the second cavity space 16. The first cavity space 12 and the second cavity space 16 are connected through the first through hole 17, and the first through hole 17 is coaxially arranged with the laser emitting end of the optical fiber structure. More specifically, the cathode housing 15 includes an integrally formed upper end plate 152 and an annular side plate 154, and a lower end plate 153 connected to the annular side plate 154. A cathode baffle 18 disposed within the cathode housing 15 divides the cathode cavity into a communicating first cavity space 12 and a second cavity space 16. The laser emission end of the fiber optic structure passes through the lower end plate 153 and extends into the second cavity space 16.

[0040] More specifically, the optical fiber structure includes a conduction structure 14, which constitutes the laser emission end of the optical fiber structure. The conduction structure 14 includes a connecting cylinder 143 fixed to the lower end plate 153, and a collimating lens 141 and a focusing lens 142 fixed inside the connecting cylinder 143 and arranged sequentially along the laser emission direction. The connecting cylinder 143 passes through the lower end plate 153 and extends into the second cavity space 16. The connecting cylinder 143 is coaxially arranged with the cathode hole 11. The laser emission direction is the axial direction of the pseudo-spark switch. The collimating lens 141 and the focusing lens 142 are disposed inside the connecting cylinder 143 and are tightly sealed to the inner wall of the connecting cylinder 143. The conduction structure 14 is used to collimate and focus the laser emitted by the laser and transmitted through the optical fiber, thereby increasing the light energy density and photoelectron density, enabling the switch to conduct quickly and stably. Furthermore, in order to reduce the output loss of the laser, the optical fiber and the two lenses mentioned above must be precisely positioned on the same optical axis, and the optical elements must be coated with anti-reflective coating. Specifically, the collimating lens 141 collimates the light with a divergence angle transmitted from the optical fiber into parallel incident light rays, which are then focused by the focusing lens 142. This can increase the light energy density, thereby increasing the density of photoelectron generation.

[0041] In one specific embodiment, the anode assembly 2 includes an anode housing 23, within which an anode cavity is formed. An anode hole 22, coaxially aligned with the cathode hole 11, is formed on the anode housing 23. The anode cavity communicates with the discharge gap 5 through the anode hole 22. The anode cavity includes a first-stage cavity 21 near the cathode assembly 1 for initial discharge and a second-stage cavity 24 away from the cathode assembly 1 for high-current conduction. The first-stage cavity 21 communicates with the discharge gap 5 through the anode hole 22. A metal partition 26 is formed within the anode housing 23. The metal partition 26 includes a second through hole 25 coaxially aligned with the anode hole 22. The first-stage cavity 21 and the second-stage cavity 24 communicate through the second through hole 25. The diameter of the second through hole 25 is larger than the diameter of the anode hole 22. The main structure of the pseudo-spark switch is formed by encapsulating an oxygen-free copper cathode housing 15 and an anode housing 23 with an insulating ceramic cylinder. The anode housing 23 specifically includes an integrally formed anode base plate 232 and an annular side plate 233, and an anode sealing plate 234 connected to the annular side plate 233. A metal partition 26 with a second through hole 25 in the middle is provided inside the anode housing 23 to divide the anode cavity into a first-level cavity 21 and a second-level cavity 24 that are connected.

[0042] The anode assembly 2 also includes a gas pipe 27 for charging and venting, fixed to the anode housing 23, which communicates with the second-stage cavity 24. The gas pipe 27 is positioned at the anode sealing plate 234, and an air hole 28 communicating with the gas pipe 27 is formed on the anode sealing plate 234. The gas pipe 27 is used for venting and charging the dummy spark switch. After charging and venting, the gas pipe 27 needs to be sealed off. The components of the dummy spark switch of this invention are welded together by brazing. Both the cathode assembly 1 and the anode assembly 2 include electrodes for connecting to an external circuit. Specifically, a cathode electrode 151 is formed on the cathode housing 15, and an anode electrode 231 is formed on the anode housing 23. An insulating ceramic cylinder is brazed and fixed between the cathode electrode 151 on the cathode housing 15 and the anode electrode 231 on the anode housing 23. Stress relief grooves 41 are formed on the side of the cathode electrode 151 and the anode electrode 231 facing away from the insulating ceramic cylinder, which reduces the welding stress during the brazing of the insulating ceramic cylinder. A positioning mounting groove 42 is formed on the side of the cathode electrode 151 and the anode electrode 231 near the insulating ceramic cylinder. The insulating ceramic cylinder is positioned and installed between the cathode electrode 151 and the anode electrode 231 through the positioning mounting groove 42, so as to realize the insulating connection between the cathode assembly 1 and the anode assembly 2.

[0043] The fiber-optic laser transmission method of this invention for triggering multiplexers can ignore the jitter of the trigger itself and the interference between multiple triggers. Furthermore, the consistency between the photoionized gas and the photocathode is extremely high, thereby improving the ignition consistency between multiplexers, enhancing the synchronous discharge capability, and achieving precise control of the trigger. This type of control can also be applied to asynchronous triggering, and precise control can still be achieved.

[0044] The fiber-optic triggered pseudo-spark switch disclosed in this invention is a gas switch operating on the left branch of the Paschen curve. Its working principle involves irradiating a photocathode with a laser of a certain energy and pulse width, causing electrons with initial kinetic energy to escape from the photocathode surface. Along the laser's conduction path, these electrons exchange energy with the working medium of the photosensitive switch—hydrogen or its isotopes—causing the gas molecules to form a weakly ionized state. Under the combined effect of these two effects, initial electrons are provided to the photosensitive switch. After the initial electrons are generated, a discharge stage begins, which can be further subdivided into the following five stages:

[0045] (1) Townsend discharge

[0046] The ignition stage of a photosensitive switch is also known as the Townsend discharge stage. The high-voltage breakdown between the anode and cathode is excited by the initial electrons generated by the ionization of the working gas during the laser irradiation of the photocathode and the transmission of the laser within the tube. Since the structural electric field inside the tube is much larger than the space charge electric field, and the mean free path of electrons is greater than the geometric distance, the discharge after the main gap breakdown cannot be self-sustaining. Only the long-range discharge at the cathode hole of the cathode assembly can maintain the electron avalanche effect.

[0047] (2) Formation of a positive ion sheath at the cathode

[0048] Through the accumulation of multiple generations of avalanche effects, a positive ion sheath first forms at the cathode aperture of the cathode assembly. These sheaths emit secondary electrons by impacting the cathode surface, increasing the gas ionization efficiency at the cathode aperture and gradually forming a stable, growing plasma region. As the plasma diffuses into the cavity, the electric field penetrating from the anode region gradually increases, and the positive ion sheath generated by the avalanche effect rapidly develops from the cathode aperture into the cavity. This is manifested externally as a rapid decrease in inter-electrode resistance, a rapid drop in anode voltage, and the initiation of current.

[0049] (3) Hollow cathode effect

[0050] A large-scale electron avalanche occurs within the cathode cavity, causing a rapid increase in the anode current, marking the beginning of the hollow cathode effect. At this point, the maximum current density inside the tube can reach 200 A / cm². 2The rapidly developing positive ion sheath provides a large number of high-energy secondary electrons to the cathode cavity. Under the confinement effect of the geometric structure, these electrons oscillate back and forth inside the cathode cavity for a sufficiently long time, and almost all of their energy is lost in collisions and ionization with gas molecules. Therefore, the gas ionization efficiency is very high.

[0051] (4) Ultra-dense glow discharge

[0052] As the plasma region within the cathode cavity increases, the sheath layer on the cavity surface is gradually compressed. This increases the electric field acting on the sheath layer and reduces the deceleration effect on secondary electrons, allowing the discharge current inside the cathode cavity to increase almost without limit. The large number of accumulated electrons eventually diffuse and migrate towards the anode cavity in the form of an electron beam; this process is called ultra-dense glow discharge. Its external characteristics include a switching voltage reduced to approximately 200V, a discharge current exceeding 60kA, and a current conduction capability as high as 10⁵ A / cm². 2 The current rise rate will also be greater than 10¹¹ A / s.

[0053] (5) Cathode electron emission enhancement and metal arc

[0054] When the thickness of the cathode sheath is compressed to less than 100 μm, the maximum electric field (≥106 V / m) can induce field emission and field thermal emission of the cathode metal, and positive ion collisions can even generate metal plasma on the electrode surface.

[0055] In summary, the fiber-optic triggered pseudo-spark switch provided by this invention is unaffected by electromagnetic interference, causes negligible ablation of the electrodes, and has a performance greater than 10. 6 The lifespan is several times that of traditional switches. Compared to the electrical triggering method of traditional switches, fiber optic triggering enables remote, non-contact, and precise control of the switch's normal operation. It can truly isolate the low-voltage control circuit from the high-voltage charging and discharging circuit in the whole system, avoiding electromagnetic interference to the control circuit during the formation of high-power pulses. Moreover, it provides a technical basis for the high-potential floating series and parallel application of switches. On the one hand, this invention covers the cathode hole of the cathode assembly with a photocathode. Utilizing the low work function of the magnesium oxide mesh structure of the photocathode, photoelectrons can be stably generated even under conditions of light energy density difference, thereby improving electron generation efficiency and laser utilization. On the other hand, the laser can weakly ionize the hydrogen gas in the discharge gap by passing through the mesh structure, which helps the pseudo-spark switch to conduct.

[0056] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A fiber-optic triggered pseudo-spark switch, characterized in that, include: The cathode assembly generates the initial electrons; An anode assembly is spaced apart from the cathode assembly, and the anode assembly provides an electric field to drive electron movement; The discharge gap is located between the cathode assembly and the anode assembly; The cathode assembly includes a cathode aperture, a cathode cavity that produces a hollow cathode effect, and a trigger for providing initial electrons; The trigger includes an optical fiber structure for transmitting laser light into the cathode cavity and a photocathode covering the cathode aperture; the laser emitting end of the optical fiber structure extends into the cathode cavity; the laser emitting end of the optical fiber structure, the photocathode, and the cathode aperture are coaxially arranged.

2. The fiber-optic triggered pseudo-spark switch according to claim 1, characterized in that, The photocathode includes a mesh portion and a sidewall portion, and at least a portion of the edge of the mesh portion is fixed to the side edge of the cathode hole opposite to the anode assembly by means of the sidewall portion.

3. The fiber-optic triggered pseudo-spark switch according to claim 1, characterized in that, The photocathode is located inside the cathode cavity.

4. The fiber-optic triggered pseudo-spark switch according to claim 2, characterized in that, The mesh portion is made of magnesium oxide.

5. The fiber-optic triggered pseudo-spark switch according to claim 1, characterized in that, The cathode assembly includes a cathode housing with a cathode cavity inside and a cathode baffle disposed inside the cathode housing. The cathode baffle includes a first through hole for laser to pass through. The first through hole is coaxially disposed with the cathode hole. The cathode housing includes an upper end plate with a cathode hole. A first cavity space for generating a hollow cathode effect is formed between the cathode baffle and the upper end plate. The cathode housing also includes a lower end plate for assembling and fixing the optical fiber structure, and a second cavity space is formed between the cathode baffle and the lower end plate; the laser emitting end of the optical fiber structure extends into the second cavity space.

6. The fiber-optic triggered pseudo-spark switch according to claim 5, characterized in that, The optical fiber structure includes a conductive structure, which constitutes the laser emission end of the optical fiber structure. The conductive structure includes a connecting cylinder fixed to the lower end plate and a collimating lens and a focusing lens arranged sequentially along the laser emission direction and fixed inside the connecting cylinder. The connecting cylinder passes through the lower end plate and extends into the second cavity space. The connecting cylinder is coaxially arranged with the cathode hole.

7. The fiber-optic triggered pseudo-spark switch according to claim 1, characterized in that, The anode assembly includes an anode housing, an anode cavity is formed inside the anode housing, an anode hole is formed on the anode housing coaxially with the cathode hole, and the anode cavity is connected to the discharge gap through the anode hole; The anode cavity includes a first-stage cavity near the cathode assembly for initial discharge and a second-stage cavity away from the cathode assembly for high-current conduction; the first-stage cavity is connected to the discharge gap through an anode hole; A metal partition is formed inside the anode housing, and the metal partition includes a second through hole coaxially arranged with the anode hole. The first-stage cavity and the second-stage cavity are connected through the second through hole.

8. The fiber-optic triggered pseudo-spark switch according to claim 7, characterized in that, The diameter of the second through hole is larger than the diameter of the anode hole.

9. The fiber-optic triggered pseudo-spark switch according to claim 7, characterized in that, The anode assembly also includes a gas pipe fixed to the anode housing for charging and venting, the gas pipe being connected to the second-stage cavity.

10. The fiber-optic triggered pseudo-spark switch according to claim 1, characterized in that, Both the cathode assembly and the anode assembly include electrodes for connection to external circuitry.

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