Pumping system and method suitable for tokamak devices having a v-shaped divertor structure

Abstract

The application provides a pumping system and method suitable for a tokamak device with a V-shaped divertor structure, and relates to the technical field of magnetic confinement nuclear fusion devices. The tokamak device comprises an inner divertor target plate, an outer divertor target plate and a baffle plate, and the outer divertor target plate corresponds to an outer divertor region with a V-shaped structure; a first leakage channel is formed between the inner divertor target plate and the baffle plate, and a second leakage channel is formed between the outer divertor target plate and the baffle plate. The pumping system comprises a pumping port and a pumping port connected with the pumping port, the pumping port is arranged on the lower side of the baffle plate and located between the common pumping region of the outlets of the two leakage channels, so as to pump the neutral particles discharged from the two leakage channels, reduce the probability of backflow of the neutral particles and the impurities from the divertor to the upstream region of the divertor, and reduce the influence of pumping on the compression and radiation conditions of the neutral particles in the outer divertor region.

Description

Technical Field

[0001] This invention relates to the field of magnetic confinement nuclear fusion device technology, and more specifically, to a pumping system and method suitable for a tokamak device with a V-type divertor structure. Background Technology

[0002] Tokamak devices utilize magnetic fields to confine plasma and receive particles and energy transported along open magnetic field lines via a divertor system. The divertor system typically includes an inner divertor region and an outer divertor region, each containing an inner and outer divertor target plate. Some tokamak devices employ a V-shaped structure for the outer divertor region to create appropriate conditions for particle transport, neutral particle compression, and energy dissipation within the outer divertor region.

[0003] Tokamak devices typically include a pumping system to remove unreacted fuel particles, helium ash, and impurities from the divertor. The operating status of the pumping system affects the neutral particle density, impurity transport, and particle distribution in the upstream region of the divertor. The pumping system generally includes a pump port and a pump connected to the port. The location of the pump port and its connection to the particle flow channels inside the divertor affect the pumping effect on different regions.

[0004] In a tokamak device with a V-type divertor structure, a leakage channel can be formed between the inner divertor target plate and the baffle, and another leakage channel can be formed between the outer divertor target plate and the baffle. Neutral particles within the divertor region can be transported along different leakage channels. When neutral particles are not extracted in time, some of them may be transported upstream of the divertor, affecting the boundary plasma density and impurity transport state.

[0005] One existing method for venting arrangement is to place the vent near the outer leakage channel, allowing for direct venting of that channel. This arrangement shortens the particle transport path between the vent and the corresponding leakage channel; therefore, when designing a venting system, the proximity of the vent to the main venting channel is usually a priority. Once the vent location is basically determined, the particle extraction capacity can be adjusted by changing the operating speed of the venting pump.

[0006] However, when the extraction port is primarily adjacent to one of the leakage channels, the extraction effect tends to concentrate on that channel, having a relatively limited impact on the neutral particle flow state in the other leakage channel. This can result in different extraction flow rate and pressure distributions between the two leakage channels, and the leakage channel that is not adequately extracted may still experience neutral particle transport to the upstream region of the divertor. Simply increasing the operating speed of the extraction pump can enhance the extraction effect of the adjacent leakage channel, but it may not necessarily improve the particle extraction state of the other leakage channel accordingly.

[0007] On the other hand, off-target operation of a divertor typically requires maintaining appropriate neutral particle density, radiation levels, and energy dissipation conditions within the outer divertor region. Enhancing particle extraction by expanding the pumping coverage or increasing the pumping speed may simultaneously reduce the neutral particle density within the outer divertor region, thereby affecting the neutral particle compression and radiation conditions in the V-shaped outer divertor region. Therefore, there is a mutual constraint between particle extraction capability and the neutral particle conditions required for off-target operation, which cannot be reconciled simply by increasing the pumping speed.

[0008] Furthermore, the transport state of impurities originating from the divertor is related to the distribution of neutral particles and the plasma flow state within the divertor region. When the pumping action is concentrated in a single leak channel, neutral particles and impurities near another leak channel may still be transported to the upstream region of the divertor, affecting impurity shielding and the control of the effective charge number of the plasma.

[0009] Therefore, for tokamak devices with a V-type divertor structure and two leakage channels, the existing evacuation arrangement still needs further coordination of the particle extraction status of the different leakage channels. The relevant evacuation system needs to ensure that both leakage channels can be effectively evacuated without excessively reducing the neutral particle compression and radiation conditions in the outer divertor region, and to reduce the degree of transport of neutral particles and divertor-source impurities to the upstream region of the divertor. Summary of the Invention

[0010] The present invention aims to solve at least one of the aforementioned technical problems existing in the prior art.

[0011] Therefore, the first aspect of the present invention provides a pumping system suitable for a tokamak device having a V-type divertor structure.

[0012] A second aspect of the present invention provides a method for evacuating air from a tokamak device having a V-type divertor structure.

[0013] This invention provides a pumping system suitable for a tokamak device with a V-shaped divertor structure. The tokamak device includes an inner divertor region, an outer divertor region, an inner divertor target plate, an outer divertor target plate, and a baffle. The inner divertor target plate is disposed in the inner divertor region, and the outer divertor target plate is disposed in the outer divertor region. The outer divertor region has a V-shaped structure. A first leakage channel is formed between the inner divertor target plate and the baffle, and a second leakage channel is formed between the outer divertor target plate and the baffle. Both the first leakage channel and the second leakage channel are connected to the divertor region of the baffle facing the plasma and the vacuum chamber pumping region of the baffle away from the plasma, and each has a first channel outlet and a second channel outlet facing the vacuum chamber pumping region. The pumping system includes a pumping unit, which includes a pumping port. The pumping port is located in the pumping area of ​​the vacuum chamber and is situated between the first channel outlet and the second channel outlet within the poloidal section of the tokamak device, and is in gas communication with the first leakage channel and the second leakage channel, respectively.

[0014] The air extraction system for a tokamak device with a V-type divertor structure according to the above-described technical solution of the present invention may further have the following additional technical features: In the above technical solution, the air extraction port is located in the middle region between the first channel outlet and the second channel outlet, and is connected to the first channel outlet and the second channel outlet through a first air extraction connection path and a second air extraction connection path, respectively. The first air extraction connection path and the second air extraction connection path are respectively located on both sides of the air extraction port in the polar section.

[0015] In the above technical solution, the air extraction unit includes an air extraction pump connected to the air extraction port, and the air extraction pump simultaneously extracts air from the first leakage channel and the second leakage channel through the air extraction port.

[0016] In the above technical solution, under the same tokamak device operating conditions and pumping speed of the pumping unit, the neutral particle flow rate from the first leakage channel to the pumping port is Q1, and the neutral particle flow rate from the second leakage channel to the pumping port is Q2. Q1 and Q2 satisfy: 0.5≤Q1 / Q2≤2.

[0017] In the above technical solution, the air pump is a cryogenic pump.

[0018] The present invention also provides a method for evacuating a tokamak device with a V-shaped divertor structure. The tokamak device includes an inner divertor region, an outer divertor region, an inner divertor target plate, an outer divertor target plate, and a baffle. The outer divertor region has a V-shaped structure. A first leakage channel is formed between the inner divertor target plate and the baffle. A second leakage channel is formed between the outer divertor target plate and the baffle. The air extraction method includes: The extraction port is located in the extraction area of ​​the vacuum chamber on the side of the baffle away from the plasma, and the extraction port is located in the poloidal section of the tokamak device between the first channel outlet of the first leakage channel and the second channel outlet of the second leakage channel. The pumping unit connected to the pumping port is activated, so that particles in the divertor region facing the plasma side of the baffle enter the pumping area of ​​the vacuum chamber through the first leakage channel and the second leakage channel, respectively, and are extracted through the pumping port.

[0019] In the above technical solution, determining the location of the air extraction port includes: Multiple candidate air extraction port locations are identified in the central region between the first channel outlet and the second channel outlet; Under the same tokamak device operating conditions and pumping speed of the pumping unit, the neutral particle flow rate Q1 of the first leakage channel and the neutral particle flow rate Q2 of the second leakage channel corresponding to each candidate pumping port position are determined respectively. The position of the air extraction port is determined from the plurality of candidate air extraction port positions based on the difference between Q1 and Q2 corresponding to each candidate air extraction port position.

[0020] In the above technical solution, the effective pumping speed of the pumping unit at the pumping port is greater than 0 and not greater than 60m. 3 / s.

[0021] In the above technical solution, the particles pumped out by the extraction unit include at least one of fuel particles, helium ash, and divertor-sourced impurities, wherein the divertor-sourced impurities include carbon impurities and / or other divertor-sourced impurities.

[0022] In the above technical solution, under the same tokamak device operating conditions and pumping speed of the pumping unit, the neutral particle flow rate from the first leakage channel to the pumping port is Q1, and the neutral particle flow rate from the second leakage channel to the pumping port is Q2. Q1 and Q2 satisfy: 0.5≤Q1 / Q2≤2.

[0023] In summary, due to the adoption of the above-mentioned technical features, the beneficial effects of the present invention are: This invention positions the extraction port in the vacuum chamber's extraction region on the side of the baffle away from the plasma, and positions it within the tokamak device's poloidal section between the first and second channel outlets. This allows the extraction port to communicate with both the first leakage channel between the inner divertor target and the baffle, and the second leakage channel between the outer divertor target and the baffle. This arrangement reduces the concentration of extraction force on a single leakage channel, allowing both leakage channels to participate in particle extraction. Specifically, the extraction port is located near the central region between the first and second channel outlets, with the first and second leakage channels forming extraction paths towards the extraction port. By strategically positioning the extraction port, the neutral particle flow rates of the two leakage channels can be coordinated, resulting in a relatively balanced extraction effect and improving the extraction system's ability to extract neutral particles from different leakage channels.

[0024] When both leakage channels participate in the pumping, the probability of neutral particles flowing back into the upstream region of the divertor through either leakage channel can be reduced, and the neutral particle density in the upstream region of the divertor can be reduced accordingly. Under the simulation conditions and the same pumping speed used in this application, compared with the comparative scheme where the pumping port is adjacent to a single-sided leakage channel, the neutral particle density in the relevant regions is reduced by approximately 40% and 61%, respectively, indicating that the position of the pumping port has an effective regulating effect on the particle pumping state of the two leakage channels.

[0025] The extraction port is located on the side of the baffle away from the plasma. The baffle creates a spatial separation between the extraction port and the external divertor region. The extraction effect is mainly transmitted through the outlet regions of the first and second leakage channels. This arrangement can reduce the direct suction effect of the extraction port on the high-density neutral particle region near the V-shaped structure of the external divertor while simultaneously extracting neutral particles from the leakage channels. This helps to preserve the neutral particle compression and radiation conditions in this region and provides the appropriate boundary conditions for the divertor to operate off-target.

[0026] The combined pumping of the two leakage channels can adjust the distribution and flow state of neutral particles within the divertor region, ensuring that more divertor-origin impurities are retained within the divertor region and reducing their transport to the upstream region and core plasma region via the leakage channels. In numerical simulations using carbon as a typical impurity, the pumping port arrangement of this invention can reduce the carbon impurity flux near the separation surface and the carbon impurity density near the outer divertor target plate, thereby improving the divertor's shielding against carbon impurities. This invention can also be used for pumping and transport control of other divertor-origin impurities with corresponding transport characteristics.

[0027] In numerical simulations where deuterium gas is injected and off-target operating conditions are established, the maximum effective charge number Zeff near the separation surface is reduced from approximately 1.16 to approximately 1.12 after adopting the exhaust port arrangement of the present invention. This result demonstrates that the present invention can balance the neutral particle conditions required for off-target operation with the transport control of impurities from the divertor source under the corresponding operating conditions.

[0028] Compared to methods that primarily rely on increasing the pumping speed of the suction pump, this invention improves the distribution of the suction effect between the two leakage channels by adjusting the spatial relationship between the suction port and the outlets of the two leakage channels. While achieving the desired particle extraction effect, it reduces the reliance on further increasing the rated pumping speed of the suction pump and allows for the selection of an appropriate pumping speed based on the operating conditions of the tokamak device.

[0029] This invention achieves dual-channel evacuation primarily through the position and connection between the evacuation port and the first leakage channel, the second leakage channel, and the baffle. It does not require the specific number of evacuation pumps, the position of the evacuation pumps relative to the vacuum chamber, or the specific form of the evacuation connection structure as necessary conditions. Therefore, it can be adapted to different types of tokamak evacuation equipment and evacuation system layouts.

[0030] Additional aspects and advantages of the invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0031] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the tokamak device and its divertor region calculation model used in an embodiment of the present invention, wherein, Figure 1 (a) is a schematic diagram of the divertor region structure of a tokamak device with a V-type divertor structure. Figure 1 (b) is a schematic diagram of the overall physical computation grid and deuterium injection location of the tokamak device. Figure 1 (c) is a schematic diagram of the local computational mesh in the divertor region; Figure 2 This is a schematic diagram showing the arrangement of different air extraction port positions, where, Figure 2 (a) Schematic diagram of the first comparative suction position set near the external divertor side of the suction port. Figure 2 (b) is a schematic diagram showing the location of the air extraction port below the baffle and in the middle area between the first channel outlet and the second channel outlet. Figure 2 (c) is a schematic diagram of the second comparative air extraction position set near the internal divertor side of the air extraction port; Figure 3 This is a comparison of the electron temperature distribution of the inner and outer divertor targets at different extraction port positions. Figure 3(a) is a comparison diagram of the electron temperature distribution of the external divertor target plate. Figure 3 (b) is a comparison diagram of the electron temperature distribution of the internal divertor target plate; Figure 4 This is a comparison diagram of the heat load distribution of the internal and external divertor target plates under different exhaust port positions. Figure 4 (a) is a comparison diagram of the heat load distribution of the external divertor target plate. Figure 4 (b) is a comparison diagram of the heat load distribution of the internal divertor target plate; Figure 5 This is a comparison of the neutral particle density distribution near the inner and outer divertor target plates at different extraction port positions. Figure 5 (a) is a comparison diagram of the neutral particle density distribution near the target plate of the external divertor. Figure 5 (b) is a comparison diagram of the neutral particle density distribution near the target plate of the internal divertor; Figure 6 This is a comparison chart of carbon impurity transport parameters at different extraction port locations. Figure 6 (a) is a comparison diagram of the carbon impurity ion flow distribution along the separation surface from the inner divertor target plate to the outer divertor target plate. Figure 6 (b) is a comparison diagram of carbon impurity density distribution near the target plate of the external divertor; Figure 7 This is a two-dimensional distribution diagram of the neutral particle density within a tokamak device at different pumping port locations. Figure 7 (a) is a neutral particle density distribution diagram when the first comparative pumping position is used. Figure 7 (b) is a neutral particle density distribution diagram when the air extraction position is located in the middle below the baffle. Figure 7 (c) is a neutral particle density distribution diagram when the second comparative pumping position is used; Figure 8 This is a two-dimensional distribution diagram of carbon atom density within a tokamak device at different pumping port positions. Figure 8 (a) is a carbon atom density distribution diagram when the first comparative pumping position is used. Figure 8 (b) is a carbon atom density distribution diagram when the air extraction position is located in the middle below the baffle. Figure 8 (c) is a carbon atom density distribution diagram when the second comparative pumping position is used; Figure 9 Comparison of Zeff distribution of effective charge number along the separation surface under different extraction port positions and deuterium injection conditions. Figure 9 (a) Comparison of the overall distribution of effective charge Zeff under the condition without deuterium injection and under the condition corresponding to different exhaust port positions. Figure 9 (b) is a comparison diagram of the local distribution of effective charge number Zeff corresponding to different pump port positions under deuterium injection conditions. Detailed Implementation

[0032] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0033] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0034] The following reference Figures 1 to 9 This invention describes a pumping system and method suitable for a tokamak device with a V-type divertor structure, provided by some embodiments of the invention.

[0035] Some embodiments of this application provide a pumping system suitable for a tokamak device with a V-type divertor structure.

[0036] This invention addresses a tokamak device with a V-shaped structure in the external divertor region and leakage channels formed between the inner divertor target plate and the baffle, as well as between the outer divertor target plate and the baffle. The pump port is positioned in the vacuum chamber pumping region on the side of the baffle away from the plasma, and is located between the outlets of the two leakage channels within the tokamak device's poloidal cross-section. This allows the pump port to simultaneously communicate with the gas in both leakage channels, ensuring that both leakage channels form neutral particle extraction paths towards the pump port. This arrangement minimizes the concentration of pumping action on a single leakage channel and reduces the direct suction impact of the pump port on the high-density neutral particle region near the V-shaped structure of the external divertor while pumping the outlet region of the leakage channel. This coordinates the neutral particle conditions required for particle extraction, impurity shielding, and divertor off-target operation.

[0037] In this embodiment, the tokamak device includes an internal divertor region, an external divertor region, an internal divertor target plate, an external divertor target plate, and a baffle. The internal divertor target plate is disposed in the internal divertor region, and the external divertor target plate is disposed in the external divertor region. The external divertor region has a V-shaped structure. The V-shaped structure refers to a partial structure or layout of the external divertor region that is V-shaped, such as... Figure 1 The external divertor target plate shown is at least partially V-shaped.

[0038] A first leakage channel is formed between the inner divertor target plate and the baffle, and a second leakage channel is formed between the outer divertor target plate and the baffle. Both the first and second leakage channels connect the divertor region facing the plasma with the baffle and the vacuum chamber pumping region facing away from the plasma with the baffle. The first leakage channel has a first channel outlet facing the vacuum chamber pumping region, and the second leakage channel has a second channel outlet facing the vacuum chamber pumping region.

[0039] The extraction system includes an extraction unit, which comprises an extraction port and an extraction pump connected to the extraction port. The extraction port is located within the extraction region of the vacuum chamber on the side of the baffle away from the plasma, and is situated between the first channel outlet and the second channel outlet within the poloidal section of the tokamak device. The extraction port is connected to the gas in the first and second leakage channels, respectively, so that neutral particles in both the first and second leakage channels can be transported to the extraction port.

[0040] The number of pumps is not limited. A pumping unit may include one pump or multiple pumps connected to the pumping port. The pump body may be located inside or outside the vacuum chamber and connected to the pumping port via a pumping connection structure. The specific location of the pump body and the pumping connection structure does not affect the positional relationship between the pumping port and the first channel outlet, the second channel outlet, and the baffle.

[0041] like Figure 1 As shown, this embodiment uses the HL-3 tokamak device as a specific example. Figure 1 The divertor configuration and corresponding computational grid of the HL-3 tokamak device are shown. The outer divertor region of the HL-3 tokamak device has a V-shaped structure, with a first leakage channel formed between the inner divertor target plate and the baffle, and a second leakage channel formed between the outer divertor target plate and the baffle. In this specific device, the first and second leakage channels extend circumferentially along the tokamak device, and therefore can also be referred to as the first circumferential leakage channel and the second circumferential leakage channel, respectively. It should be noted that the HL-3 tokamak device is only used to illustrate a specific application of the present invention, and the present invention can also be applied to other tokamak devices with the same or similar divertor structure and leakage channel layout. Figure 1 (a) illustrates the divertor region structure of a tokamak device, which includes an inner divertor region and an outer divertor region, wherein the outer divertor region has a V-shaped structure. The inner and outer divertor targets are used to receive plasma particles and energy transported along open magnetic field lines, respectively. A baffle is used to limit the transport range of neutral particles within the divertor region and to form a corresponding spatial separation between the divertor region and the pumping region in the vacuum chamber below the baffle.

[0042] Figure 1(b) shows the overall physical computation grid of the tokamak device and the location of the deuterium injection. Figure 1 (c) shows the local computational grid of the divertor region. In this embodiment, the boundary plasma transport numerical simulation program SOLPS-ITER (Scrape-Off Layer Plasma Simulation-ITER, the International Thermonuclear Experimental Reactor scraped layer plasma simulation program) is used to calculate the plasma, neutral particle, and impurity transport states at different pumping port locations. SOLPS-ITER is used to establish numerical models of the boundary plasma region and divertor region of the tokamak device, and to perform coupled calculations of plasma particle transport, energy transport, neutral particle transport, and impurity transport.

[0043] The numerical model includes the magnetic balance of the tokamak device, the divertor structure, the inner divertor target plate, the outer divertor target plate, the baffle, the first leakage channel, the second leakage channel, and the pumping area inside the vacuum chamber. The local mesh of the divertor region is divided according to the actual boundaries of the inner divertor target plate, the outer divertor target plate, and the baffle, so that the computational mesh can characterize the particle transport state of the first leakage channel, the second leakage channel, and the vicinity of the outlets of the two channels.

[0044] The specific numerical solution method for SOLPS-ITER can employ the known coupled calculation methods for boundary plasma fluid transport and neutral particle transport. When comparing calculations at different pumping port locations, the same or corresponding magnetic balance, input power, upstream plasma boundary conditions, wall recirculation conditions, impurity source conditions, and pumping boundary conditions are used to ensure comparability of calculation results for different pumping port locations. The pumping port can be set as a pumping boundary with a given effective pumping velocity in the numerical model, or the corresponding particle absorption probability can be set according to the pumping port area, the thermal motion state of neutral particles, and the performance of the pump.

[0045] This embodiment uses SOLPS-ITER as the numerical simulation tool, but the present invention is not limited to using this program. In other embodiments, other numerical models capable of calculating plasma transport, neutral particle transport, and impurity transport can also be used, or parameters such as particle flow rate, neutral particle density, target plate electron temperature, target plate thermal load, impurity density, and plasma effective charge number at different pumping port positions can be obtained through tokamak device operation experiments.

[0046] exist Figure 1(b) In one specific embodiment, deuterium gas (D2) is injected into the tokamak device to establish or maintain the neutral particle and radiation conditions required for off-target operation of the divertor. The deuterium injection location can be set according to the divertor structure and operating conditions. Deuterium injection is not a necessary condition for the pumping system to achieve dual-channel pumping, but is used to study the influence of different pumping port positions on neutral particle distribution and impurity transport under off-target operation conditions.

[0047] like Figure 2 As shown, Figure 2 Three different air extraction port locations are shown. Figure 2 (a) shows the extraction position CryopumpA located near the external divertor side and adjacent to the second leakage channel. Figure 2 (b) shows the pumping position Cryopump B located in the pumping region of the vacuum chamber on the side of the baffle away from the plasma, and in the middle region between the first channel outlet and the second channel outlet in the poloidal section. Figure 2 (c) shows the extraction position Cryopump C located near the internal divertor side and adjacent to the first leakage channel.

[0048] Extraction positions Cryopump A and Cryopump C are used for comparison with extraction position Cryopump B. Extraction position Cryopump A is primarily adjacent to the second leakage channel, and its extraction effect is easily concentrated on the external divertor side; extraction position Cryopump C is primarily adjacent to the first leakage channel, and its extraction effect is easily concentrated on the internal divertor side. Extraction position Cryopump B is located between the outlets of the two channels, allowing the extraction port to connect to the first channel outlet via a first extraction connection path and to the second channel outlet via a second extraction connection path. The first and second extraction connection paths are located on opposite sides of the extraction port within the poloidal section.

[0049] In this embodiment, the extraction position Cryopump B corresponds to the extraction port position of the present invention, while extraction positions Cryopump A and Cryopump C are only used as comparison positions to verify the influence of the extraction position. Extraction positions Cryopump A and Cryopump C are not candidate extraction positions used when optimizing the position in the central region between the first channel outlet and the second channel outlet.

[0050] In some embodiments, the central region between the first channel outlet and the second channel outlet refers to the area located within the poloidal cross section between the first channel outlet and the second channel outlet, capable of forming gas communication paths to both channel outlets respectively. This central region is not required to be the exact midpoint of the line connecting the geometric centers of the first and second channel outlets, nor is it required that the geometric distances from the extraction port to the two channel outlets be exactly equal. The specific extent of the central region can be determined based on the location of the two channel outlets, the channel cross-sectional area, the length of the extraction path, and the gas flow direction.

[0051] The pumping point Cryopump B is located below the baffle and adjacent to the areas where the first and second channel outlets are located. The baffle is positioned between the pumping port and the divertor region on the plasma-facing side of the baffle, thus preventing the pumping port from being directly located in the high-density neutral particle region near the V-shaped structure of the external divertor. The pumping action is transmitted to the plasma-facing side of the baffle via the first and second leakage channels, thus preferentially pumping out neutral particles transported to the vicinity of the two channel outlets and reducing the probability of neutral particles flowing back into the upstream region of the divertor through the corresponding leakage channels.

[0052] Maintaining a certain neutral particle density within the divertor region facilitates atomic and molecular processes such as charge exchange, collisions, and recombination between neutral particles and the plasma. This promotes momentum loss and energy dissipation in the plasma, providing the necessary conditions for high recycle operation or off-target operation. If the exhaust port directly faces the high-density neutral particle region within the external divertor region, or if excessive suction is applied to this region, it may reduce the neutral particle compression in that region and affect the aforementioned momentum loss and energy dissipation processes. In this embodiment, the exhaust port is positioned below the baffle and between the outlets of the first and second channels. This ensures that the suction effect is primarily applied to the neutral particles discharged through the two leakage channels. The baffle spatially separates the exhaust port from the high-density neutral particle region within the external divertor region, thereby reducing the direct impact of the suction process on the neutral particle compression conditions within the external divertor region.

[0053] The specific shape, opening direction, and opening size of the extraction port can be set according to the relative position of the first channel outlet and the second channel outlet, the space under the baffle, the target extraction flow rate, and the rated pumping speed of the extraction pump. The extraction port can be directed towards the common extraction area between the two leakage channel outlets, or it can be deflected towards at least one of the first channel outlet and the second channel outlet without directly facing the high-density neutral particle area within the external divertor region.

[0054] In some embodiments, the pump is a cryogenic pump. The cryogenic pump can be a cryogenic condenser pump and / or a cryogenic adsorption pump, which captures deuterium, helium, and other neutral gas particles by maintaining a cryogenic surface within the pump at a temperature suitable for the condensation or adsorption of the gas to be pumped. In one specific embodiment, the operating temperature of the cryogenic surface can be in the liquid helium temperature range, for example, about 4.5 K or lower; the specific operating temperature can be determined according to the type of gas to be pumped, the cryogenic surface material, and the cryogenic pump structure. This invention is not limited to a specific type of cryogenic pump; other vacuum pumps capable of achieving the required pumping effect in a corresponding vacuum environment can also be used.

[0055] In some embodiments, the evacuation system may further include an evacuation pipeline connected to the evacuation port and the evacuation pump, valves disposed on the evacuation pipeline, and measurement and control components. The measurement and control components may include a vacuum gauge, a pressure sensor, a gas composition detection device, and / or a mass spectrometer, for detecting the neutral gas pressure, gas composition, and evacuation pump operating status in the area below the baffle or in the evacuation pipeline. The valves may adjust their opening degree according to the operating stage of the tokamak device to regulate the evacuation flow rate. The specific arrangement of the evacuation pipeline, valves, and measurement and control components described above does not constitute a limitation on the positional relationship of the evacuation port.

[0056] During operation of the pumping system, the pump forms a pumping boundary at the pumping port. Neutral particles in the divertor region facing the plasma enter the first and second leakage channels, respectively. Neutral particles in the first leakage channel enter the pumping area within the vacuum chamber through the first channel outlet and flow towards the pumping port along the first pumping connection path; neutral particles in the second leakage channel enter the pumping area within the vacuum chamber through the second channel outlet and flow towards the pumping port along the second pumping connection path. Both groups of neutral particles are extracted by the pumping unit through the pumping port.

[0057] During the operation of a tokamak device, the pumping system is used not only to remove fuel particles such as deuterium, but also to remove helium ash and impurities from the divertor. The particle balance and recirculation level within the device are regulated by adjusting the effective pumping speed of the pump or the valve opening. Different effective pumping speeds can be used at different stages, such as discharge start-up, main plasma heating, steady-state operation, and discharge termination. The corresponding adjustments should be based on meeting the device's vacuum conditions, fuel particle replenishment requirements, and divertor operating conditions.

[0058] In some embodiments, cross sections for calculating neutral particle flow rates can be set at the outlets of the first and second channels, respectively. The neutral particle flow rate flowing from the first leakage channel to the extraction port is denoted as Q1, and the neutral particle flow rate flowing from the second leakage channel to the extraction port is denoted as Q2. The neutral particle flow rate can be obtained by integrating the neutral particle flux at the channel outlet cross section. Alternatively, Q1 and Q2 can be obtained by a particle flux detection device installed at the channel outlet or by pressure / conductivity conversion.

[0059] In one specific embodiment, under the same tokamak device operating conditions and pumping speed of the pumping unit, the position of the pumping port is set such that Q1 and Q2 satisfy 0.5 ≤ Q1 / Q2 ≤ 2. This flow ratio range is used to characterize that both the first and second leakage channels bear the corresponding neutral particle extraction flow rates, rather than strictly requiring Q1 and Q2 to be exactly equal; an approximate equilibrium state is sufficient. For example, among candidate pumping port positions where the sum of Q1 and Q2 reaches a preset total extraction flow rate, the candidate pumping port position with Q1 / Q2 closest to 1 is selected as the pumping port position. The pumping port can be appropriately offset to one side according to the cross-sectional area, conductance, and neutral particle source distribution of the two channels to compensate for the differences in the structure of the two leakage channels or the particle source conditions.

[0060] In some embodiments, multiple candidate pumping port locations can be determined in the central region between the first channel outlet and the second channel outlet. For each candidate pumping port location, under the same plasma operating conditions, deuterium injection conditions, and effective pumping speed of the pumping unit, the corresponding Q1 and Q2 are calculated or measured respectively. The pumping port location can be determined from multiple candidate pumping port locations based on the difference between Q1 and Q2, the deviation of Q1 / Q2 from 1, and the total pumping flow rate of the two channels. When it is necessary to consider the divertor's target detachment operation, the neutral particle density of the external divertor region, the target plate electron temperature, the target plate thermal load, or the radiation power can also be used as location determination conditions.

[0061] The above-described method of comparing candidate locations within the central region is an implementation method for refining the determination of the air extraction port location. Figure 2 The pumping positions Cryopump A and Cryopump C are located outside the central region and are mainly used to illustrate the difference between the unilateral pumping position and the central pumping position. They are not part of the candidate position selection step within the central region mentioned above.

[0062] In some embodiments, the effective pumping speed of the pumping unit at the pumping port is greater than 0 and not greater than 60 m / s. 3 / s. Effective pumping speed refers to the pumping velocity at the pumping port location, taking into account the pumping port, the pumping connection structure, and the pumping capacity of the pump. The rated pumping speed of the pump can be calculated based on the conductance loss of the pumping connection structure to obtain the effective pumping speed at the pumping port. A pumping speed of 0 can be used as a comparative condition for no pumping effect; in implementing the pumping method of this invention, the effective pumping speed is greater than 0.

[0063] This embodiment prioritizes improving the utilization of the pumping effect by coordinating the location of the extraction port with the outlets of the two leakage channels, rather than solely relying on increasing the rated pumping speed of the pump to achieve the target exhaust effect. Under the same rated pumping speed, the extraction port located within the common extraction area can simultaneously receive neutral particles discharged through both leakage channels, thereby improving the utilization of the pumping capacity in both leakage directions. While meeting the target neutral particle discharge rate, upstream neutral particle density, and divertor operating conditions, a pump with a relatively lower rated pumping speed can also be selected to reduce the configuration burden of the pump and its associated cryogenic, piping, and valve systems. The actual rated pumping speed used should be determined based on the device dimensions, leakage channel conductance, and operating conditions.

[0064] The pumping speed of the pumping unit can be set according to the plasma density, input power, deuterium injection rate, divertor off-target state, and particle discharge requirements of the tokamak device. Since the pumping port is connected to the gas of both the first and second leakage channels, the particle flow state of the two leakage channels can be adjusted simultaneously at the corresponding effective pumping speed, thereby reducing the need to improve the pumping state of the other leakage channel by increasing the pumping speed of only one pumping port.

[0065] like Figure 3 As shown, Figure 3 The electron temperature distribution of the inner and outer divertor targets is shown at different exhaust port positions. Figure 3 (a) shows the electron temperature distribution of the external divertor target plate. Figure 3 (b) shows the electron temperature distribution of the internal divertor target plate. The horizontal axis represents the radial coordinate of the target plate position relative to the separation surface position, and the vertical axis represents the electron temperature, in electron volts (eV).

[0066] Depend on Figure 3It can be seen that the target plate electron temperature distribution trends at pumping positions Cryopump A (corresponding to the black line pump a), Cryopump B (corresponding to the blue line pump b), and Cryopump C (corresponding to the red line pump c) are generally consistent. Different pumping positions mainly alter the electron temperature values ​​near the impact point and its adjacent areas. Using pumping position Cryopump B allows maintaining the electron temperature distribution of both the inner and outer divertor target plates within their respective operating ranges even when both leakage channels participate in pumping. The target plate electron temperature can be combined with neutral particle density, thermal load, and radiation status to determine whether the divertor is in a state of or close to being out of target.

[0067] like Figure 4 As shown, Figure 4 The heat load distribution of the inner and outer divertor targets is shown at different exhaust port positions. Figure 4 (a) shows the heat load distribution of the external divertor target plate. Figure 4 (b) shows the heat load distribution of the internal divertor target plate. When different exhaust port positions are used, the overall trend of the target plate heat load curve is similar, but the local heat load near the impact point is different.

[0068] In this embodiment, electron temperature and thermal load are used to evaluate the changes in the divertor target plate operating state after changing the pumping port position. The pumping position Cryopump B does not achieve particle control by directly reducing the electron temperature or thermal load at all target plate positions. Instead, it changes the neutral particle transport state in the two leakage channels and the upstream region of the divertor while maintaining the target plate electron temperature and thermal load distribution to meet the corresponding operating requirements.

[0069] Under the same calculation boundary conditions, input power, and particle source conditions, the changes in electron temperature near the target plate and target plate thermal load with the pumping position can be used to indirectly evaluate the impact of different pumping positions on particle balance and plasma state in the divertor region. For example, at the same rated pumping speed, a greater increase in electron temperature near the target plate usually indicates that the corresponding pumping position has a significant impact on local neutral particles and the recirculation process. However, target plate electron temperature is not the only evaluation parameter for pumping efficiency; it should also be considered in conjunction with pumping flow rate, neutral particle density distribution, target plate thermal load, and divertor deflection status for a comprehensive assessment.

[0070] like Figure 5 As shown, Figure 5 The distribution of neutral particle density near the inner and outer divertor targets is shown at different exhaust port positions. Figure 5 (a) shows the neutral particle density distribution near the target plate of the external divertor. Figure 5(b) shows the neutral particle density distribution near the target plate of the internal divertor. Compared with Cryopump A and Cryopump C, Cryopump B can simultaneously change the neutral particle density distribution on both the internal and external divertor sides and reduce the peak neutral particle density in the relevant upstream region.

[0071] Under the same pumping speed and corresponding boundary conditions, after adopting the pumping position Cryopump B, the neutral particle density characteristic values ​​near the impact point of the external divertor and the impact point of the internal divertor are reduced by approximately 40% and 61%, respectively, compared to the corresponding operating conditions of the single-sided pumping positions (pumping positions Cryopump A and Cryopump C). These percentages are results from the calculated operating conditions of this embodiment, used to illustrate that placing the pumping port in the common pumping area can simultaneously affect the neutral particle transport corresponding to the two leakage channels, and do not constitute a limitation on the specific reduction percentage under other devices or other operating conditions. Combined with... Figure 7 The two-dimensional neutral particle density distribution shown also indicates that the evacuation position Cryopump B can reduce the density of neutral particles flowing back to the upstream region of the divertor through the two leakage channels, while preventing the high-density area in the outer divertor region, which is responsible for the compression and radiation of neutral particles, from being over-evacuated.

[0072] The region of reduced neutral particle density is primarily located upstream of the divertor, rather than near the V-shaped structure of the outer divertor, which is responsible for maintaining neutral particle compression and radiation conditions. This is because the evacuation port is located on the side of the baffle away from the plasma, creating a spatial separation between the evacuation port and the outer divertor region. The evacuation port mainly draws in neutral particles entering near the exits of the first and second channels. Therefore, the evacuation location, Cryopump B, reduces the probability of neutral particles flowing back through the leakage channel while preserving the neutral particle compression and radiation conditions near the V-shaped structure of the outer divertor.

[0073] like Figure 6 As shown, Figure 6 The variations in carbon impurity transport parameters at different extraction port locations are shown. Figure 6 (a) shows the distribution of carbon impurity ion flow along the separation surface from the inner divertor target plate to the outer divertor target plate. Figure 6 (b) shows the carbon impurity density distribution near the target plate of the external divertor. The positive and negative directions of the carbon impurity ion flow are as follows: Figure 6 The coordinate direction shown in (a) is determined.

[0074] In this embodiment, carbon impurities can originate from physical and / or chemical sputtering of components after being bombarded by plasma from a target plate, baffle, or other plasma surface. Carbon impurities entering the boundary plasma can be in a neutral state or different ionized states. When ionized carbon impurities are transported along magnetic field lines, they are affected by background plasma friction, thermal forces, and electric fields. Changing the pumping position can further influence the ionization position and convective transport direction of carbon impurities by altering the local neutral particle distribution, the recirculation process, and boundary plasma parameters.

[0075] Placing the extraction port between the two leakage channel outlets creates a relatively concentrated particle discharge path near the leakage channel outlets, reducing the probability of neutral carbon impurities or impurity particles formed after the plasma ions are neutralized near the component being transported to the upstream region of the divertor. Simultaneously, the modified boundary plasma parameters can enhance the transport of some impurities towards the target plate, confining the impurities more within the divertor region. The specific transport behaviors under different impurity types and operating conditions can be determined using appropriate plasma transport, neutral particle transport, and impurity transport models, or through experimental measurements.

[0076] When using Cryopump B as the pumping position, the carbon impurity ion flux in the relevant section of the separation surface and the carbon impurity density near the external divertor target are lower than those corresponding to Cryopump A and Cryopump C. This result indicates that adjusting the neutral particle transport state by Cryopump B can affect the transport of carbon impurities within the divertor region, keeping more carbon impurities within the divertor region and reducing their transport to the upstream region of the divertor.

[0077] In this embodiment, carbon impurities are calculated as representative of impurities originating from the divertor. The particles pumped or controlled by the pumping unit may include at least one of fuel particles, helium ash, and impurities originating from the divertor. Fuel particles may include neutral particles formed by the recombination of deuterium atoms, deuterium molecules, or corresponding ions at the wall surface; helium ash may recombine or undergo charge exchange within the divertor region to form pumpable particles; impurities originating from the divertor may include carbon impurities, tungsten impurities, and other impurities generated by the target plate, baffle, or other plasma surface components. Carbon impurities are used as a specific calculation and illustrative object in this embodiment and do not imply that the pumping system and pumping method of the present invention are only applicable to carbon impurities.

[0078] For divertor-source impurities other than carbon, corresponding atomic parameters and boundary conditions can be set in the numerical model based on the ionization, recombination, sputtering, and wall recirculation characteristics of the impurities, or their density and flux in the divertor region and upstream region can be measured through device operation tests. The location of the extraction port in this invention does not depend on a specific impurity type; its function is based on simultaneously adjusting the transport of neutral particles and related impurities within the first and second leakage channels.

[0079] like Figure 7 As shown, Figure 7 The two-dimensional distribution of neutral particle density corresponding to the three air extraction port locations is shown. Figure 7 (a) Corresponding to the pumping position Cryopump A, Figure 7 (b) Corresponding to the pumping position Cryopump B, Figure 7 (c) Corresponding pumping position CryopumpC. The three operating conditions use the same or corresponding plasma boundary conditions and pumping speed of the pumping unit.

[0080] Depend on Figure 7 (a) It can be seen that when the extraction port is near the external divertor side, the extraction effect mainly affects the second leakage channel and its adjacent area, while the area corresponding to the first leakage channel still has a relatively high neutral particle density. Figure 7 (c) It can be seen that when the air extraction port is close to the internal divertor side, the air extraction effect mainly affects the first leakage channel and its adjacent area, while the neutral particle extraction state of the area corresponding to the second leakage channel is relatively weak.

[0081] Depend on Figure 7 (b) It can be seen that when the extraction port is located below the baffle and between the first channel outlet and the second channel outlet, the extraction effect can be transmitted to the first leakage channel and the second leakage channel through the two channel outlets respectively, so that the overall neutral particle density in the upstream region of the divertor is lower than that in the corresponding working condition of the single-sided extraction position. At the same time, the area near the V-shaped structure of the external divertor still maintains the corresponding neutral particle density distribution, and there is no local direct suction state formed by the extraction port being directly arranged in this high-density area.

[0082] like Figure 8 As shown, Figure 8 The two-dimensional distribution of carbon atom density at different exhaust port locations is shown. Figure 8 (a) Corresponding to the pumping position Cryopump A, Figure 8 (b) Corresponding to the pumping position Cryopump B, Figure 8 (c) Corresponding pumping position Cryopump C. The carbon atom density distribution reflects the spatial transport state of carbon impurities in the divertor region, the boundary plasma region, and the upstream region.

[0083] When Cryopump A or Cryopump C is used for evacuation, carbon atoms are distributed along the corresponding insufficiently evacuated leakage channels and the upstream region of the divertor. When Cryopump B is used for evacuation, both the first and second leakage channels are evacuated, the density of carbon atoms in the upstream region of the divertor decreases, and they remain more concentrated within the divertor region. Figure 8 The results shown are the same as Figure 6 The results show the carbon impurity ion flow and the carbon impurity density near the target plate of the external divertor.

[0084] like Figure 9 As shown, Figure 9 The distribution of plasma effective charge number Zeff along the separation surface under different pumping port locations and deuterium injection conditions is shown. The plasma effective charge number Zeff is used to characterize the comprehensive influence of impurity ions on the charge state in the plasma, and its value varies with impurity type, impurity density, and ionization state.

[0085] Figure 9 (a) shows the overall Zeff distribution under the operating condition without deuterium injection and under the operating conditions corresponding to different pump port positions. Without deuterium injection (no puff), the maximum Zeff along the separation surface is approximately 1.9. After deuterium injection and the establishment of corresponding off-target operating conditions, the Zeff corresponding to different pump port positions is lower than that under the operating condition without deuterium injection. Since the operating conditions without deuterium injection and those with deuterium injection use different boundary conditions, they are used to illustrate the impact of changes in operating conditions on impurity transport states and are not used as a direct comparison to evaluate the effect of pump port positions alone.

[0086] Figure 9 (b) shows the local Zeff distribution at pumping positions Cryopump A, Cryopump B, and Cryopump C under deuterium injection conditions. With pumping positions Cryopump A and Cryopump C, the maximum Zeff along the separation surface is approximately 1.15 to 1.16; with pumping position Cryopump B, the maximum Zeff along the separation surface is approximately 1.12. This result indicates that, under the same or corresponding deuterium injection and pumping operating conditions, pumping position Cryopump B can reduce the transport of divertor-sourced impurities to the separation surface and upstream region.

[0087] comprehensive Figures 3 to 9The results showed that the location of the extraction port affected the target plate electronic temperature, target plate thermal load, neutral particle density, carbon impurity flux, carbon impurity density, and Zeff. Positioning the extraction port below the baffle and between the first and second channel outlets allows both leakage channels to participate in particle extraction without solely relying on increasing the pumping speed. This reduces the neutral particle density and impurity transport in the upstream region of the divertor, while preserving the neutral particle compression and radiation conditions near the V-shaped structure of the external divertor.

[0088] Other embodiments of the present invention provide a pumping method that may include the following steps: determining a first leakage channel and a second leakage channel based on the positions of the inner divertor target plate, the outer divertor target plate, and the baffle of the tokamak device; determining the positions of the first channel outlet and the second channel outlet within the poloidal section; setting the pumping port between the two channel outlets in the pumping area of ​​the vacuum chamber on the side of the baffle away from the plasma; connecting the pumping port to a pumping pump; starting the pumping pump so that particles in the divertor area enter the pumping area of ​​the vacuum chamber through the first leakage channel and the second leakage channel, respectively, and are extracted through the pumping port.

[0089] During operation, the effective pumping speed of the pumping unit can be adjusted according to the plasma operating status of the tokamak device. When adjusting the pumping speed, one or more parameters can be monitored or calculated, including target plate electronic temperature, target plate thermal load, neutral particle density in the divertor region, neutral particle density in the upstream region of the divertor, neutral particle flow rate in the first and second leakage channels, impurity density, impurity flux, and Zeff. The pumping speed setting should meet the particle discharge requirements of the device and maintain the corresponding divertor operating status.

[0090] The above embodiment is used as an example of a tokamak device with a V-shaped structure in the divertor region and two leakage channels. When the specific geometric dimensions of the tokamak device, the shape of the baffle, the cross-sectional area of ​​the two leakage channels, or the shape of the pumping area in the vacuum chamber change, the position of the pumping port between the outlets of the two channels can be adjusted accordingly without changing the technical concept that the pumping port is simultaneously connected to the gas of the first leakage channel and the second leakage channel.

[0091] The above description describes the embodiments of the present invention. Without departing from the technical concept of the present invention, corresponding adjustments can be made to the size and shape of the air extraction port, the type and number of air pumps, the air extraction connection method, the operating speed of the air extraction unit, and the specific position of the air extraction port between the two channel outlets; all of these adjustments can be used to implement the present invention.

[0092] In this specification, the illustrative expressions of the terms used do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0093] Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention shall be included within the scope of protection of this invention.

Claims

1. A pumping system suitable for a tokamak device with a V-type divertor structure, characterized in that, The tokamak device includes an internal divertor region, an external divertor region, an internal divertor target plate, an external divertor target plate, and a baffle. The internal divertor target plate is disposed in the internal divertor region, and the external divertor target plate is disposed in the external divertor region. The external divertor region has a V-shaped structure. A first leakage channel is formed between the inner divertor target plate and the baffle, and a second leakage channel is formed between the outer divertor target plate and the baffle. Both the first leakage channel and the second leakage channel are connected to the divertor region of the baffle facing the plasma and the vacuum chamber pumping region of the baffle away from the plasma, and each has a first channel outlet and a second channel outlet facing the vacuum chamber pumping region. The pumping system includes a pumping unit, which includes a pumping port. The pumping port is located in the pumping area of ​​the vacuum chamber and is situated between the first channel outlet and the second channel outlet within the poloidal section of the tokamak device, and is in gas communication with the first leakage channel and the second leakage channel, respectively.

2. The pumping system for a tokamak device with a V-type divertor structure according to claim 1, characterized in that, The air extraction port is located in the middle region between the first channel outlet and the second channel outlet, and is connected to the first channel outlet and the second channel outlet through a first air extraction connection path and a second air extraction connection path, respectively. The first air extraction connection path and the second air extraction connection path are respectively located on both sides of the air extraction port in the polar section.

3. The pumping system for a tokamak device with a V-type divertor structure according to claim 1, characterized in that, The air extraction unit includes an air pump connected to the air extraction port, which simultaneously extracts air from the first leakage channel and the second leakage channel through the air extraction port.

4. The pumping system for a tokamak device with a V-type divertor structure according to claim 1, characterized in that, Under the same tokamak device operating conditions and pumping speed of the pumping unit, the flow rate of neutral particles flowing from the first leakage channel to the pumping port is Q1, and the flow rate of neutral particles flowing from the second leakage channel to the pumping port is Q2. Q1 and Q2 satisfy: 0.5≤Q1 / Q2≤2.

5. The pumping system for a tokamak device with a V-type divertor structure according to claim 3, characterized in that, The air pump is a cryogenic pump.

6. A method for evacuating air from a tokamak device with a V-type divertor structure, characterized in that, The tokamak device includes an internal divertor region, an external divertor region, an internal divertor target plate, an external divertor target plate, and a baffle. The external divertor region has a V-shaped structure. A first leakage channel is formed between the internal divertor target plate and the baffle, and a second leakage channel is formed between the external divertor target plate and the baffle. The air extraction method includes: The extraction port is located in the extraction area of ​​the vacuum chamber on the side of the baffle away from the plasma, and the extraction port is located in the poloidal section of the tokamak device between the first channel outlet of the first leakage channel and the second channel outlet of the second leakage channel. The pumping unit connected to the pumping port is activated, so that particles in the divertor region facing the plasma side of the baffle enter the pumping area of ​​the vacuum chamber through the first leakage channel and the second leakage channel, respectively, and are extracted through the pumping port.

7. The evacuation method for a tokamak device with a V-type divertor structure according to claim 6, characterized in that, Determining the location of the air extraction port includes: Multiple candidate air extraction port locations are identified in the central region between the first channel outlet and the second channel outlet; Under the same tokamak device operating conditions and pumping speed of the pumping unit, the neutral particle flow rate Q1 of the first leakage channel and the neutral particle flow rate Q2 of the second leakage channel corresponding to each candidate pumping port position are determined respectively. The position of the air extraction port is determined from the plurality of candidate air extraction port positions based on the difference between Q1 and Q2 corresponding to each candidate air extraction port position.

8. The method for pumping air into a tokamak device with a V-type divertor structure according to claim 6, characterized in that, The effective pumping speed of the pumping unit at the pumping port is greater than 0 and not greater than 60 m / s. 3 / s.

9. The method for pumping air into a tokamak device with a V-type divertor structure according to claim 6, characterized in that, The particles extracted by the extraction unit include at least one of fuel particles, helium ash, and divertor-sourced impurities, wherein the divertor-sourced impurities include carbon impurities and / or other divertor-sourced impurities.

10. The method for pumping air into a tokamak device with a V-type divertor structure according to claim 6, characterized in that, Under the same tokamak device operating conditions and pumping speed of the pumping unit, the flow rate of neutral particles flowing from the first leakage channel to the pumping port is Q1, and the flow rate of neutral particles flowing from the second leakage channel to the pumping port is Q2. Q1 and Q2 satisfy: 0.5≤Q1 / Q2≤2.

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