Compact X-point slot closed divertor

Abstract

The invention relates to the technical field of divertors, and discloses a compact X-point slot closed divertor, which comprises a weak field side far scraping layer reflecting plate unit, a hidden flux region unit and a strong field side scraping layer reflecting plate unit, the area, far away from the first side edge of the weak field side far scraping layer reflecting plate unit, of the second side edge of the weak field side far scraping layer reflecting plate unit is the striking point position of particles; the main plasma on the strong field side scraping layer reflecting plate unit is coupled with the weak field side far scraping layer reflecting plate unit; the hidden flux area unit is arranged between the weak field side far scraping layer reflecting plate unit and the strong field side scraping layer reflecting plate unit, and is used for changing the speed direction of recirculated particles into the direction vertical to the outermost closed magnetic surface; and gaps are respectively formed between the hidden flux area unit and the weak field side far scraping layer reflecting plate unit and between the hidden flux area unit and the strong field side far scraping layer reflecting plate unit so as to form a first extraction opening and a second extraction opening. According to the invention, the energy dissociation capability of the divertor is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of divertors, and particularly to a compact X-point slot-closed divertor. Background Art

[0002] During the steady-state operation of a fusion reactor, the high heat load borne by the divertor target plate is a key issue, especially in high-magnetic-field and compact fusion devices. The scrape-off layer heat flux width in these devices is typically less than 1 mm, resulting in a very high scrape-off layer parallel heat flux, which may reach the GW / m 2 level, such as: SPARC, thus leading to a parallel heat flux deposited on the target plate that will also be as high as GW / m 2 level. Therefore, effectively controlling the high heat load on the target plate is a core challenge in magnetic confinement fusion research. Under steady-state operating conditions, a tungsten divertor target plate can withstand a heat flux density of up to 10 MW / m 2 However, high plasma temperatures and strong particle fluxes may cause sputtering of the target plate material, releasing a large number of impurity particles, thereby affecting the confinement performance of the plasma.

[0003] Fortunately, scientists have found that by achieving divertor detachment, the heat flux density, electron temperature, and particle flux on the target plate can be significantly reduced, thus effectively protecting the divertor. For example, the International Thermonuclear Experimental Reactor (ITER) project adopts divertor detachment operation. Therefore, researchers have been exploring effective methods to promote divertor detachment. Research shows that by optimizing the divertor geometry, magnetic field configuration, and using external means (such as injecting radiating impurity gases, strike point scanning, etc.), it is beneficial for the divertor to achieve the goal of detachment. Experimental and simulation studies have proven that a closed divertor can effectively enclose the recycled particles and radiating impurity particles in the divertor region. Compared with an open divertor, it significantly reduces the heat flux density on the target plate and promotes plasma detachment. In addition, a closed divertor can also improve the confinement performance of the core plasma. Therefore, several tokamak devices, including DIII-D, JT-60, EAST, and MAST, have been upgraded with closed divertors.

[0004] HL-3, a medium-sized tokamak device, has successfully achieved high-confinement mode operation when the plasma current reaches 1 MA. Currently, the device only has a lower divertor and lacks an upper divertor. The lower divertor is designed with an open geometry to accommodate various snowflake divertor configurations. To further advance ITER's research in burning plasma physics and engineering technologies, HL-3 is preparing for deuterium-tritium (D-T) experiments. Achieving this goal requires upgrading HL-3's heating system to a total power of 20 MW. At the same time, to improve the discharge performance of the device, HL-3 will adopt a double-null divertor with a large elongation ratio to increase the core plasma volume. Given that currently only the lower divertor is installed on HL-3, the installation of the upper divertor has become particularly urgent. Summary of the Invention

[0005] Based on the above research background, the present invention provides a compact X-point slot-closed divertor on the HL-3 tokamak device. Compared with traditional divertors, this new type of divertor effectively couples a relatively large V-shaped geometry with the scrape-off layer main plasma, significantly increasing the contact area between the main plasma and the divertor structure, enhancing the confinement of recycled particles in the divertor and the energy loss volume, avoiding the overheating problem of local V-shaped corners. Moreover, due to the relatively short distance between the X-point and the DOME, the space of the shadow flux region is reduced, increasing the interaction space between the main scrape-off layer plasma and the large V-shaped structure. This enables this new type of divertor to reduce the space of the shadow flux region, significantly reducing the asymmetric transport of particle flows between the inner and outer divertors, further enhancing the impurity screening ability of this compact X-point slot-closed divertor. Through numerical simulation using the large-scale edge code SOLPS-ITER, it is found that the compact X-point slot-closed divertor of the present invention is very conducive to achieving detachment, reducing the heat flux on the target plate, and is expected to solve the high heat load problem in future fusion reactors.

[0006] The present invention is achieved through the following technical solutions:

[0007] A compact X-point slot-closed divertor, comprising a semi-closed structure composed of a weak-field side far scrape-off layer reflector unit, a shadow flux region unit, and a strong-field side scrape-off layer reflector unit. The distance between the weak-field side far scrape-off layer reflector unit and the strong-field side scrape-off layer reflector unit in this semi-closed structure gradually increases from the closed end to the open end. Among them,

[0008] The weak-field-side far scrape-off layer reflector unit has a large-angle V-shaped structure. The area where the second side of the weak-field-side far scrape-off layer reflector unit is far from the first side of the weak-field-side far scrape-off layer reflector unit is the particle impact point position. When particles impact on the second side of the weak-field-side far scrape-off layer reflector unit, they are recycled. And the main plasma located on the weak-field-side far scrape-off layer reflector unit is coupled with the structure of the weak-field-side far scrape-off layer reflector unit.

[0009] The hidden flux region unit is arranged between the weak-field-side far scrape-off layer reflector unit and the strong-field-side scrape-off layer reflector unit, and is used to change the velocity direction of the recycled particles to the direction pointing to the outermost closed magnetic surface. And gaps are respectively provided between the hidden flux region unit and the weak-field-side far scrape-off layer reflector unit and the strong-field-side scrape-off layer reflector unit to form a first pumping port and a second pumping port. The impact point position is located between the first pumping port and the first side of the weak-field-side far scrape-off layer reflector unit, and a cryopump for cooperating with the first pumping port and the second pumping port for pumping is arranged outside the semi-closed structure.

[0010] As an optimization, the hidden flux region unit has a V-shaped structure, and a gap is provided between the first side of the hidden flux region unit and the end of the second side of the weak-field-side far scrape-off layer reflector unit that is not connected to the first side of the weak-field-side far scrape-off layer reflector unit to form the first pumping port, and the extension line of the first side of the hidden flux region unit and the second side of the weak-field-side far scrape-off layer reflector unit form a V-shaped structure.

[0011] A gap is provided between the end of the second side of the hidden flux region unit and the first end of the strong-field-side scrape-off layer reflector unit to form the second pumping port, and the strong-field-side scrape-off layer reflector unit and the extension line of the second side of the hidden flux region unit form a V-shaped structure, and the apex of the hidden flux region unit faces the inside of the semi-closed structure.

[0012] As an optimization, the weak-field-side far scrape-off layer reflector unit includes a first weak-field-side far scrape-off layer particle reflection baffle and a second weak-field-side far scrape-off layer particle reflection baffle that form a large-angle V-shaped structure. The second weak-field-side far scrape-off layer particle reflection baffle is the second side of the weak-field-side far scrape-off layer reflector unit. Among them, the first weak-field-side far scrape-off layer particle reflection baffle is composed of a first straight baffle, a second straight baffle, and an arc baffle arranged on the first straight baffle and the second straight baffle. The arc baffle

[0013] The first straight baffle is smoothly and transitionally connected to the second straight baffle through the arc baffle. The opening direction of the arc baffle faces the outside of the semi-closed structure. The second weakly-field-side far scrape-off layer particle reflection baffle is a third straight baffle, and a large-angle V-shaped structure is formed between the first straight baffle and the third straight baffle.

[0014] As an optimization, the concealed flux region unit includes a weakly-field-side concealed flux region particle reflection baffle as the first side of the concealed flux region unit and a strongly-field-side concealed flux region particle reflection baffle as the second side of the concealed flux region unit. The weakly-field-side concealed flux region particle reflection baffle and the strongly-field-side concealed flux region particle reflection baffle form a V-shaped structure, and the opening of this V-shaped structure faces the outside of the semi-closed structure. The first air extraction port is located between the weakly-field-side concealed flux region particle reflection baffle and the second weakly-field-side far scrape-off layer particle reflection baffle.

[0015] As an optimization, the strongly-field-side scrape-off layer reflection plate unit includes a strongly-field-side scrape-off layer particle reflection baffle. The strongly-field-side scrape-off layer particle reflection baffle is composed of a fourth straight baffle and a fifth straight baffle, and the opening of the V-shaped structure formed by the fourth straight baffle and the fifth straight baffle faces the outside of the semi-closed structure. The second air extraction port is located between the strongly-field-side concealed flux region particle reflection baffle and the fourth straight baffle.

[0016] As an optimization, two cryopumps are provided. One cryopump is located in the opening area of the concealed flux region unit, and the other cryopump is located on the side of the weakly-field-side far scrape-off layer reflection plate unit away from the semi-closed structure.

[0017] As an optimization, the vertical distance between the X-point of the compact X-point slot closed divertor and the vault is less than 3 cm.

[0018] As an optimization, the distance between the strike point position and the intersection point of the extension line of the weakly-field-side concealed flux region particle reflection baffle and the second weakly-field-side far scrape-off layer particle reflection baffle is less than 2 cm.

[0019] As an optimization, the sizes of the first air extraction port and the second air extraction port range from 40 mm to 60 mm.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] This kind of compact X-point slot closed divertor can combine the advantages of various existing international closed divertors, and has been optimized and improved on the basis of various advanced closed divertors, mainly including:

[0022] (1) By setting the compact divertor into a W shape, the present invention enables the HL-3 Tokamak to achieve a large elongation double null configuration within a limited device space, which is conducive to improving the device operation parameters;

[0023] (2) The present invention utilizes the advantage of the strong recycling particle confinement of the SAS divertor. However, since the SAS divertor concentrates the recycling particles in the shadow flux region, the electric drift in the divertor region will almost cancel out the contribution of the SAS divertor geometry to detachment. Therefore, the present invention transfers the region where the recycled neutral particles are concentrated to the scrape-off layer region, enhancing the energy dissociation ability of the divertor;

[0024] (3) The present invention combines the advantage of the strong particle confinement ability of the small-angle V-shaped divertor. However, since the small-angle V-shaped divertor not only poses strict requirements for control, but also because the recycled particles are mainly concentrated at the V-shaped corners, it may lead to limited energy dissociation ability of this type of divertor. Therefore, based on the advantages and disadvantages of the small-angle V-shaped divertor, the XSC divertor of the present invention can couple the large-angle V-shaped divertor structure with the scrape-off layer main plasma, greatly improving the energy dissociation ability and reducing the requirements for control;

[0025] (4) The present invention combines the advantages of the compact radiative divertor (CRD). However, this type of divertor easily causes radiative impurity particles to enter the core plasma region from the X-point, which is not conducive to the removal of helium ash in future fusion reactors. Moreover, this type of divertor has extremely high requirements for operation control, otherwise it is very easy to cause a discharge breakdown. The compact X-point slot-closed divertor of the present invention can couple the CRD divertor with the slot-closed divertor, effectively confining the impurity particles far from the X-point, reducing the risk of impurity accumulation in the core, and enhancing its particle control ability at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, form a part of this application, and do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0027] Figure 1 is a schematic structural diagram of the compact X-point slot-closed divertor described in the present invention;

[0028] Figure 2 is the neutral particle density distribution of the compact X-point slot-closed divertor described in the present invention;

[0029] Figure 3 is the comparison distribution of the electron temperature and heat flux of the target plates of the compact X-point slot-closed divertor and the open divertor described in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] To make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to embodiments and drawings. The illustrative embodiments and descriptions thereof of the present invention are only used to explain the present invention and shall not be construed as a limitation to the present invention.

[0031] Embodiment 1 of the present invention provides a compact X-point slot-closed divertor, as Figure 1 shown, which includes a semi-closed structure composed of a weak-field side far scrape-off layer reflector unit, a shadow flux region unit, and a strong-field side scrape-off layer reflector unit. The distance between the weak-field side far scrape-off layer reflector unit and the strong-field side scrape-off layer reflector unit in this semi-closed structure gradually increases from the closed end to the open end. Among them,

[0032] the weak-field side far scrape-off layer reflector unit has a large-angle V-shaped structure. The area where the second side of the weak-field side far scrape-off layer reflector unit is far from the first side of the weak-field side far scrape-off layer reflector unit is the impact point position of particles. When the particles impact on the second side of the weak-field side far scrape-off layer reflector unit, they are recycled; and the main plasma on the weak-field side far scrape-off layer reflector unit is coupled with the structure of the weak-field side far scrape-off layer reflector unit; that is, all the main plasma on the weak-field side far scrape-off layer reflector unit is deposited on the weak-field side far scrape-off layer reflector unit.

[0033] The so-called structure coupling here means that all the main plasma hits the weak-field side far scrape-off layer reflector unit.

[0034] In the present invention, the large angle in the large-angle V-shaped structure of the weak-field side far scrape-off layer reflector unit ranges from [90°, 120°].

[0035] The shadow flux region unit is arranged between the weak-field side far scrape-off layer reflector unit and the strong-field side scrape-off layer reflector unit, and is used to change the velocity direction of the recycled particles to the direction pointing to the outermost closed magnetic surface. And gaps are respectively arranged between the shadow flux region unit and the weak-field side far scrape-off layer reflector unit and the strong-field side scrape-off layer reflector unit to form a first pumping port and a second pumping port. The impact point position is located between the first pumping port and the first side of the weak-field side far scrape-off layer reflector unit, and a cryopump for cooperating with the first pumping port and the second pumping port for pumping is arranged outside the semi-closed structure.

[0036] In some embodiments, the concealed flux region unit has a V-shaped structure, and there is a gap between the first side of the concealed flux region unit and the end of the second side of the weak-field side far scrape-off layer reflector unit that is not connected to the first side of the weak-field side far scrape-off layer reflector unit to form the first air extraction port, and the extension line of the first side of the concealed flux region unit and the second side of the weak-field side far scrape-off layer reflector unit form a V-shaped structure;

[0037] There is a gap between the end of the second side of the concealed flux region unit and the first end of the strong-field side scrape-off layer reflector unit to form the second air extraction port, and the strong-field side scrape-off layer reflector unit and the extension line of the second side of the concealed flux region unit form a V-shaped structure, and the apex of the concealed flux region unit faces the inside of the semi-closed structure.

[0038] In some embodiments, the weak-field side far scrape-off layer reflector unit includes a first weak-field side far scrape-off layer particle reflection baffle and a second weak-field side far scrape-off layer particle reflection baffle that form a large-angle V-shaped structure. The second weak-field side far scrape-off layer particle reflection baffle is the second side of the weak-field side far scrape-off layer reflector unit. Among them, the first weak-field side far scrape-off layer particle reflection baffle is composed of a first straight baffle, a second straight baffle, and an arc-shaped baffle provided on the first straight baffle and the second straight baffle. The arc-shaped baffle;

[0039] The first straight baffle is smoothly connected to the second straight baffle through the arc-shaped baffle. The opening direction of the arc-shaped baffle faces the outside of the semi-closed structure. The second weak-field side far scrape-off layer particle reflection baffle is a third straight baffle, and a large-angle V-shaped structure is formed between the first straight baffle and the third straight baffle.

[0040] As Figure 1 shown, the first weak-field side far scrape-off layer particle reflection baffle baffle 1# is formed by connecting two straight baffles (1 and 2, 1 is the first straight baffle, 2 is the second straight baffle) and an arc-shaped structure (3, 3 is the arc-shaped baffle). It should be noted here that the entire first weak-field side far scrape-off layer particle reflection baffle baffle 1# is composed of divertor structure materials and does not include first wall materials. The main reason is that during the operation of the device, due to configuration control and other perturbations, part of the plasma will be deposited on the second straight baffle 2. If it is a first wall material, it is easily damaged. In addition, the design of the second straight baffle 2 will enable the tokamak device (HL-3 in this embodiment) to achieve an advanced inverse triangular configuration.

[0041] The particle reflection baffle baffle 2# on the second weak field side far scrape-off layer is connected to the particle reflection baffle baffle 1# on the first weak field side far scrape-off layer. The two together form a large-angle V-shaped closed divertor. Compared with the past small-angle V-shaped divertor, this large-angle V-shaped divertor can enhance the volume of the divertor energy radiation loss. In order to enhance the configuration control ability of this XSC divertor, the present invention reserves a space of 5 cm for the length of the particle reflection baffle baffle 2# on the second weak field side far scrape-off layer.

[0042] In some embodiments, the concealed flux region unit includes a particle reflection baffle on the weak field side of the concealed flux region as the first side of the concealed flux region unit and a particle reflection baffle on the strong field side of the concealed flux region as the second side of the concealed flux region unit. The particle reflection baffle on the weak field side of the concealed flux region and the particle reflection baffle on the strong field side of the concealed flux region form a V-shaped structure, and the opening of the V-shaped structure faces the outside of the semi-closed structure. The first air extraction port is located between the particle reflection baffle on the weak field side of the concealed flux region and the particle reflection baffle on the second weak field side far scrape-off layer. The distance between the position of the strike point and the intersection point of the extension line of the particle reflection baffle on the weak field side of the concealed flux region and the particle reflection baffle on the second weak field side far scrape-off layer is less than 2 cm.

[0043] Specifically, the particle reflection baffle baffle 3# on the weak field side of the concealed flux region, the particle reflection baffle baffle 2# on the second weak field side far scrape-off layer, and the particle reflection baffle baffle 1# on the first weak field side far scrape-off layer together form a slot-closed divertor.

[0044] The particle reflection baffle baffle 4# on the strong field side of the concealed flux region and the particle reflection baffle baffle 3# on the weak field side of the concealed flux region together form a W-shaped compact divertor dome.

[0045] In some embodiments, the strong field side scrape-off layer reflection plate unit includes a particle reflection baffle on the strong field side scrape-off layer. The particle reflection baffle on the strong field side scrape-off layer is composed of a fourth straight baffle and a fifth straight baffle, and the opening of the V-shaped structure formed by the fourth straight baffle and the fifth straight baffle faces the outside of the semi-closed structure. The second air extraction port is located between the particle reflection baffle on the strong field side of the concealed flux region and the fourth straight baffle.

[0046] The particle reflection baffle 5# on the high-field side scrape-off layer and the particle reflection baffle 4# in the high-field side hidden flux region together form a V-shaped divertor, whose purpose is to reflect the recycled particles at the V-shaped corner, enhancing the pumping capacity of the HL-3 divertor. The particle reflection baffle 5# on the high-field side scrape-off layer consists of two straight target plates, including the fourth straight baffle 4 and the fifth straight baffle 5. The fourth straight baffle 4 will mainly bear the high heat flux bombardment flowing into the divertor, while the fifth straight baffle 5 will prevent part of the heat flux from being deposited on the first wall of the tokamak device due to configuration control factors.

[0047] In some embodiments, two cryopumps are provided, one of which is located in the opening area of the hidden flux region unit, and the other cryopump is located on the side of the weak-field side far scrape-off layer reflector unit away from the semi-closed structure.

[0048] Two cryopumps are set here to enhance the particle control ability of the divertor.

[0049] In some embodiments, the first pumping port 6 is the particle pumping port of the weak-field side divertor, that is Figure 1 the pumping port on the right side in the figure; since the pumping capacity of the cryopump mainly depends on the neutral particle pressure in the divertor region, the higher the pressure of the neutral particles, the stronger the pumping capacity. Otherwise, the divertor will face the problem of particle control. Since the main heat flux will be mainly deposited on the weak-field side divertor region (i.e., the weak-field side far scrape-off layer reflector unit), the weak-field side divertor (baffle1#, baffle2#, baffle3#) will first face the problem of high heat load, and the high heat load will mean that the neutral particle pressure in the weak-field side divertor region is relatively low. Therefore, the primary task of the weak-field side divertor is to reduce the heat flux deposited on the target plate through divertor radiation loss, and then increase the neutral particle pressure in the divertor region, so as to further improve the particle control ability of the weak-field side divertor. Therefore, the position of the particle pumping port (the first pumping port) on the weak-field side is set at the leftmost side of the second weak-field side far scrape-off layer particle reflection baffle baffle2#.

[0050] The second pumping port 7 is the particle pumping port of the strong-field side divertor. Since the heat flux of the strong-field side divertor (baffle 4#, baffle 5#) is relatively lower than that of the weak-field side divertor, it is easier to achieve detachment at the strong-field side divertor. Therefore, the primary task of the strong-field side divertor is particle pumping. Otherwise, a large number of recycled particles accumulate at the strong-field side divertor, which will cause radiation losses to enter the X-point, leading to the rupture of the discharge plasma. Therefore, in the present invention, the position of the strong-field side divertor particle pumping port (the second pumping port) is set between the particle reflection baffle baffle 4# in the hidden flux region on the strong-field side and the particle reflection baffle baffle 5# in the scrape-off layer on the strong-field side, so that a large number of recycled particles will be directly reflected into the second pumping port, enhancing the particle control ability of the divertor.

[0051] The installation positions of the two cryopumps are as Figure 1 shown, Figure 1 in which the region of (9) is a large elongation ratio double null configuration (the elongation ratio of the magnetic field configuration is about 1.8).

[0052] The position of the outermost closed magnetic surface and the strike point of the double null divertor configuration is as Figure 1 shown in (10) and (11) in it.

[0053] In Figure 1 it, the position where the strike point needs to be injected is in the range on the left side of the second weak-field side far scrape-off layer particle reflection baffle baffle 2#. The purpose is to jointly form a large-angle V-shaped divertor with the first weak-field side far scrape-off layer particle reflection baffle baffle 1# and the second weak-field side far scrape-off layer particle reflection baffle baffle 2#. Here, setting the large-angle V-shaped divertor effectively utilizes the advantage of the strong heat load control energy of the past DIII-D small-angle V-shaped divertor. However, in the past small-angle V-shaped divertor, since the main recycled particles were concentrated at the vertex of the V corner, the radiation losses would mainly concentrate there, resulting in relatively small energy dissociation ability of the small-angle V-shaped divertor. Moreover, this small-angle V-shaped divertor poses strict requirements for the control of the divertor configuration. Therefore, in the present invention, by increasing the angle of the V-shaped divertor, the energy dissociation space of the divertor is significantly increased, the energy radiation loss of the compact X-point slot closed divertor of the present invention is enhanced, which is conducive to achieving detachment and heat load control, and at the same time, the configuration control ability is enhanced.

[0054] The position of the X-point of the compact X-point slot closed divertor is as Figure 1As shown in (12) therein. It should be noted here that: Point X is near the top of the vault formed by the particle reflection baffle baffle 3# in the weak-field-side hidden flux region and the particle reflection baffle baffle 4# in the strong-field-side hidden flux region, and the vertical height (vertical distance) from the top of the vault is less than 3 cm. It can be understood as the closest distance from the top of the vault to point X. This invention makes use of the advantages of the Compact Radial Divertor (CRD). However, in the past, the CRD divertor of the German AUG device faced the risk of impurity particles entering the core. This invention patent combines the X-point compact divertor with the slot-closed divertor, thus solving the risk of impurity particles entering the core plasma.

[0055] In summary, during the fusion reaction process of the fusion reactor, a large amount of heat flux will be transported from the core plasma into the scrape-off layer through radial reverse-field transport (the scrape-off layer is the channel for transporting the heat flux to the baffles (each reflector)), and this heat flux will further flow into the divertor through the poloidal magnetic field lines. Since the energy flux flowing into the divertor from the core will be mainly concentrated in the scrape-off layer region (the right side of the above particle strike point position), rather than the hidden flux region of the divertor (the left side of the above strike point position), a large amount of plasma will be directly deposited on the large-angle V-shaped divertor structure. Part of the plasma flow is deposited on the baffle 1# particle reflector, and the other part of the plasma flow is deposited on the baffle 2#. Due to the strong particle recycling of baffle 1#, a large number of recycled particles are reflected into the scrape-off layer plasma region of the divertor, and a large number of recycled particles will be ionized, thus radiating a large amount of energy. Moreover, baffle 1#, baffle 2# and the particle reflector baffle 3# in the hidden flux region work together to change the movement direction of the recycled particles. The movement direction of a large number of recycled particles is perpendicular to the outermost closed magnetic surface, enhancing the confinement of the invented X-point slot-closed divertor to the recycled particles and impurity particles, improving the divertor detachment ability and heat load control ability, increasing the neutral particle pressure in the divertor region, facilitating effective particle control, suppressing the entry of impurities into the core, and improving the confinement performance of the core plasma.

[0056] Furthermore, by scanning the strike point on the particle reflection baffle baffle 2#, the heat flux on the target plate can be effectively reduced. Here, the main thing is that: the range of the movement scan of the strike point position is controlled within 3 cm from the lower end of baffle 3#. If it exceeds this range, the detachment and heat load control capabilities will be reduced.

[0057] Baffle 1#, baffle 2# and baffle 3# together form the outer divertor. Among them, baffle 1# consists of three sections of target plate structures, including two sections of straight baffles (1, 2) and one section of target plate structure with a curvature (3). The main functions of the two sections are to prevent the deposition of the strike point on the first wall, enhance the interaction between the particles in the far scrape-off layer and the first wall, reflect some of the recycled particles into the weak-field side divertor region, and enhance the energy dissociation ability of the divertor. In addition, the two-section divertor structure can achieve an inverted triangular divertor, enabling the invented divertor to be compatible with multiple divertor configurations. Baffle 1# and baffle 2# together form a large-angle V-shaped divertor. At the same time, by combining the scrape-off layer main plasma with this V-shaped structure, the radiation loss volume of the divertor is greatly enhanced, which is more conducive to the control of the thermal load. In order to change the movement direction of the recycled particles in the divertor region, the present invention adds a particle reflector baffle 3# in the hidden flux region on the weak-field side, which can change the velocity direction of the recycled particles to be perpendicular to the outermost closed magnetic surface, more effectively confining the recycled particles in the divertor region. At the same time, the influence of the electric drift in the divertor region is weakened.

[0058] The particle reflectors baffle 4# and baffle 5# on the high-field side together form the high-field side divertor. Among them, baffle 4# and baffle 3# together form the dome, weakening the asymmetric transport of particles in the divertor region. The particle reflector baffle 5# consists of two sections, 4 and 5. The function of section 5 of the reflector is to prevent the plasma from directly depositing on the first wall of the device; while section 4 mainly receives the plasma flow from the upper core, and together with baffle 4# forms a V-shaped closed divertor structure, gathering the recycled neutral particles at the pumping port position, enhancing the pumping ability of the divertor, suppressing the backflow of impurities on the high-field side into the core plasma, and improving the confinement performance of the core plasma.

[0059] As Figure 2 shown, the edge plasma code SOLPS-ITER was used to conduct numerical simulation studies on the compact X-point slot closed divertor of the present invention, and corresponding comparisons were made with the open lower divertor. Its main parameters include: the heating power is 20 MW; the density at the outermost closed magnetic surface is ~3×10 19 m -3 , considering the physical and chemical sputtering of carbon impurity particles, where the chemical sputtering factor is 3%; considering the electromagnetic drift factors in the divertor region. During the simulation process, neon impurities were injected at the divertor strike point, with an injection rate of ~1×10 20 / s. The simulation results show that compared with the open divertor, the compact X-point slot closed divertor of the present invention is very conducive to achieving off-target and thermal load mitigation.

[0060] Under the condition of the same upstream plasma parameters, the heat flux and electron temperature deposited on the compact X-point slot closed divertor are 3 MW / m 2 and 5 eV (as shown in Figure 2 and Figure 3 ); it shows that the divertor has achieved detachment. On the contrary, the heat flux and electron temperature of the open divertor target plate are much higher than those of the compact X-point slot closed divertor, which are 15 MW / m 2 and 35 eV, as shown in Figure 3 .

[0061] Example 2 discloses a tokamak device, and the detachment of the divertor is achieved by using a compact X-point slot closed divertor of Example 1.

[0062] The above specific implementation manners further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific implementation manners of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A compact X-point slot closed divertor, characterized in that: The invention comprises a semi-enclosed structure composed of a weak field side far scraping layer reflector unit, a hidden flux zone unit and a strong field side scraping layer reflector unit, wherein the distance between the weak field side far scraping layer reflector unit and the strong field side scraping layer reflector unit in the semi-enclosed structure gradually increases from the closed end to the open end, wherein: The weak field side far scraping layer reflector unit is in a large-angle V-shaped structure, the second side of the weak field side far scraping layer reflector unit is away from the first side of the weak field side far scraping layer reflector unit as the impact point of the particles, and the particles are recycled after impacting the second side of the weak field side far scraping layer reflector unit; and the main plasma located on the weak field side far scraping layer reflector unit is coupled with the weak field side far scraping layer reflector unit structure; The hidden flux zone unit is arranged between the weak field side far scraping layer reflector unit and the strong field side scraping layer reflector unit, and is used to change the speed direction of the recycled particles to point to the direction of the outermost closed magnetic surface, and gaps are respectively arranged between the hidden flux zone unit and the weak field side far scraping layer reflector unit and the strong field side scraping layer reflector unit to form a first vacuum port and a second vacuum port, the striking point position is located between the first vacuum port and the first side edge of the weak field side far scraping layer reflector unit, and a low-temperature pump that cooperates with the first vacuum port and the second vacuum port for vacuuming is arranged on the outside of the semi-enclosed structure.

2. A compact X-point slot closed divertor according to claim 1, characterized in that: The concealed flux zone unit is in a V-shaped structure, and a gap is provided between the first side of the concealed flux zone unit and the end of the second side of the weak field side far scraping layer reflector unit that is not connected to the first side of the weak field side far scraping layer reflector unit to form the first air extraction port, and the extension line of the first side of the concealed flux zone unit forms a V-shaped structure with the second side of the weak field side far scraping layer reflector unit; A gap is arranged between the end of the second side of the hidden flux zone unit and the first end of the strong field side scraping layer reflector unit to form the second air suction port, and the extension line of the strong field side scraping layer reflector unit and the second side of the hidden flux zone unit forms a V-shaped structure, and the dome of the hidden flux zone unit faces the interior of the semi-enclosed structure.

3. A compact X-point slot closed divertor according to claim 1, characterized in that: The weak field side far scraping layer reflector unit comprises a first weak field side far scraping layer particle reflector baffle and a second weak field side far scraping layer particle reflector baffle forming a large angle V-shaped structure, wherein the second weak field side far scraping layer particle reflector baffle is the second side of the weak field side far scraping layer reflector unit, wherein the first weak field side far scraping layer particle reflector baffle is composed of a first straight baffle, a second straight baffle, and an arc baffle arranged on the first straight baffle and the second straight baffle, wherein the arc baffle The first straight baffle is smoothly connected to the second straight baffle through the arc baffle, the opening direction of the arc baffle is toward the outside of the semi-closed structure, the second weak field side far scraping layer particle reflection baffle is the third straight baffle, and a large-angle V-shaped structure is formed between the first straight baffle and the third straight baffle.

4. A compact X-point slot closed divertor according to claim 3, characterized in that: The hidden flux zone unit includes a weak field side hidden flux zone particle reflection baffle as the first side of the hidden flux zone unit and a strong field side hidden flux zone particle reflection baffle as the second side of the hidden flux zone unit. The weak field side hidden flux zone particle reflection baffle and the strong field side hidden flux zone particle reflection baffle are in a V-shaped structure, and the opening of the V-shaped structure faces the outside of the semi-closed structure. The first air exhaust port is located between the weak field side hidden flux zone particle reflection baffle and the second weak field side far-scraping layer particle reflection baffle.

5. A compact X-point slot closed divertor according to claim 4, characterized in that: The strong field side scraping layer reflector unit includes a strong field side scraping layer particle reflective baffle, the strong field side scraping layer particle reflective baffle is composed of a fourth straight baffle and a fifth straight baffle, and the opening of the V-shaped structure formed by the fourth straight baffle and the fifth straight baffle faces the outside of the semi-closed structure, and the second air exhaust port is located between the strong field side hidden flux area particle reflective baffle and the fourth straight baffle.

6. A compact X-point slot closed divertor according to claim 2, characterized in that: Two cryopumps are provided, one of which is located in the opening area of ​​the concealed flux zone unit, and the other is located on the side of the weak field side far scraped layer reflector unit away from the semi-enclosed structure.

7. A compact X-point slot closed divertor according to claim 2, characterized in that: The vertical distance between the X-point of the compact X-point slot closed divertor and the dome is less than 3 cm.

8. A compact X-point slot closed divertor according to claim 4, characterized in that: The distance between the strike point position and the intersection of the extension line of the particle reflection baffle in the hidden flux zone on the weak field side and the particle reflection baffle in the far scraping layer on the second weak field side is less than 2 cm.

9. A compact X-point slot closed divertor according to claim 1, characterized in that: The size range of the first air suction port and the second air suction port is 40 mm to 60 mm.

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