• 专利附录
  • 专利说明
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    • 专利摘要:
    Representative pellets (208) may be used for magnetic fusion devices to mitigate disruption of a plasma (204). In some embodiments, the pellets may be cryogenically cooled, which may cause an increase in the electrical conductivity of the pellets. High conductivity of the pellets can block the magnetic field of the plasma from inside the pellet. Locking of the magnetic field of the plasma can reduce the ablation rate of the pellet, which may allow deeper penetration of the pellet and a better spatial profile of the deposited material for appropriate attenuation of plasma disruption. In some other embodiments, the pellets may not be cryogenically cooled.
    公开号:FR3076054A1
    申请号:FR1860647
    申请日:2018-11-16
    公开日:2019-06-28
    发明作者:Paul Brownlee Parks
    申请人:General Atomics Corp；
    IPC主号:
    专利说明:

    TECHNICAL AREA
    This patent relates to systems, devices and methods relating to thermonuclear fusion technology.
    BACKGROUND
    A tokamak is a device that uses a magnetic field to spatially confine a plasma, for example in the form of a torus, to produce a plasma at high temperature necessary for the production of controlled thermonuclear fusion energy. Magnetic fields are used in tokamak devices for containment, in part because solid materials cannot withstand the extremely high temperatures of plasma for thermonuclear fusion. In a tokamak, a stable plasma equilibrium can be obtained by producing lines of magnetic field which move around the torus in a helical form. Such a helical field can be generated by adding a toroidal field which moves around the torus in circles and a poloidal field which moves in circles orthogonal to the toroidal field. In certain embodiments, the toroidal field can be produced by electromagnets which surround the toroid, and the poloidal field can be produced by a toroidal electric current which circulates inside the plasma and can be induced inside the plasma, by example by using a second set of electromagnets. At large toroid currents, various magnetic confinement fusion devices tend to exhibit unwanted plasma instabilities. The non-linear evolution of these plasma instabilities can lead to an extinction of the plasma current in a short period of time, for example of the order of milliseconds. This extinction can create energetic decoupled electrons which escape from the spatially confined plasma and can potentially lead to a rapid loss of the plasma confinement. Such decoupled electrons can collide with components that face the plasma and can damage the components, for example by inflicting intense heat on such components. This phenomenon is called a disruption of the plasma.
    ABSTRACT
    Techniques, systems and devices are described for representative pellets usable for magnetic fusion devices to mitigate disruption of plasma. Representative tablets can reduce plasma disruption while entering the plasma. Thus, the technology disclosed can amplify the penetration depth of the pellets and can allow the pellets to reach the central core of the plasma. Representative pellets can also be introduced into magnetic melting devices in the form of a hollow shell comprising an interior payload of small granules or porous material, thereby reducing the potential for damage to the wall away from the device. magnetic fusion in the event of an accidental impact.
    A representative embodiment discloses a fusion device. The representative melter includes a plasma vessel structured to include a hollow interior for confining the plasma, a plurality of toroidal field coils wound around different portions of an exterior surface of the plasma vessel, the plurality of coils toroidal field being configured to magnetically confine the plasma within the plasma vessel, a storage device which stores pellets, and a tablet injector positioned to receive pellets from the storage device and operable to inject the pellets into the plasma tank.
    In some embodiments, the storage device is a cryostat storage device that stores and cools the pellets, and where the pellets have metallic exteriors. In some embodiments, the cryostat storage device is configured to cool the plurality of pellets to a temperature less than or equal to 40 Kelvin (K). In some embodiments, the cryostat storage device is configured to cool the plurality of pellets to a temperature of 10 Kelvin (K).
    In some embodiments, the pellets include solid pellets. In some embodiments, the pellets include hollow shell pellets. In some embodiments, each hollow shell pellet encapsulates a payload. In some embodiments, the payload includes granules or a porous material. In some embodiments, the payload includes lithium, lithium deuteride, beryllium, beryllium deuteride, boron, boron nitride, or tungsten. In some embodiments, each tablet contains lithium or beryllium.
    In some embodiments, the plasma vessel is in the form of a D-shaped torus. In some embodiments, the pellet injector includes a single stage light gas cannon.
    In some other embodiments, each pellet includes a hollow shell which encapsulates a payload. In certain other embodiments, the hollow shell comprises lithium, lithium deuteride, beryllium, beryllium deuteride, or boron nitride.
    In some other embodiments, the payload includes lithium, lithium deuteride, beryllium, beryllium deuteride, boron, boron nitride, or tungsten.
    Another embodiment discloses a method for attenuating the disruption of the plasma. The representative method includes magnetic confinement of the plasma in a plasma tank, storage of pellets, and injection of the pellets stored in the plasma tank. In certain embodiments, the representative method further comprises cooling the pellets stored to a temperature less than or equal to 40 kelvins (K). In some embodiments, the pellets are cooled to about 10 Kelvin (K).
    BRIEF DESCRIPTION OF THE DRAWINGS
    Figure 1 shows a cross-sectional view of a representative magnetic fusion device.
    Figure 2 shows the concept of magnetic shielding for a representative patch.
    Figure 3 shows a plot of resistivity as a function of temperature for the representative lithium and beryllium samples.
    FIGS. 4A to 4D show simulations of the magnetic configuration surrounding a light metal pellet during representative ablation, cooled to 40 Kelvin (K).
    FIGS. 4A to 4D show simulations of the magnetic configuration surrounding a light metal pellet during representative ablation, cooled to 40 Kelvin (K).
    FIGS. 4A to 4D show simulations of the magnetic configuration surrounding a light metal pellet during representative ablation, cooled to 40 Kelvin (K).
    FIGS. 4A to 4D show simulations of the magnetic configuration surrounding a light metal pellet during representative ablation, cooled to 40 Kelvin (K).
    FIG. 5 illustrates a representative method of injecting a pellet into a magnetic melting device.
    Figure 6 shows a cross section of another representative patch.
    DETAILED DESCRIPTION
    Based on the technology disclosed in this document, in the operation of a magnetic confinement fusion device such as a tokamak, pellets can be injected into hot fusion plasma to attenuate unwanted disruption of the plasma. However, the pellets injected tend to vaporize quickly because of the heat caused by the hot melting plasma. This vaporization can limit the penetration depth of the pellets injected into the hot melting plasma. Penetration of the pellets to the core of the confined plasma before complete vaporization can reduce unwanted disruption of the plasma. The interaction of the plasma with the ablated material of the pellets can cause the plasma to radiate its thermal energy, thereby disseminating it over a large area instead of allowing an uncontrolled loss of thermal energy towards the components facing the plasma surrounding the device. of fusion. Plasmas can be confined by nested magnetic flux surfaces, but when these surfaces are ruptured during a plasma disruption, the plasma thermal energy can quickly escape to the structures of surrounding materials, causing damage. The technology disclosed in this document can be used to mitigate plasma disruptions based in part on a design and control of the chemical composition, structure, or temperature of representative pellets. In some embodiments, the structure of the representative pellets may include a shell and materials inside the shell, called payload. The shell and the payload, once dispersed in the plasma, can be ionized by the plasma and can allow energy to radiate out of the plasma. Representative pellets can help mitigate plasma disruption in part because the shell of the pellets can be used to transport at least part of the payload into the plasma before a certain part of the payload begins to ionize . Representative embodiments disclose both cooled and uncooled pellets, which may differ by the distance over which the shell can penetrate the plasma before the shell decays, releasing both the shell material and the payload in plasma.
    The illustrative embodiments firstly describe pellets which can be cryogenic cooled before introducing the pellets into a magnetic confinement melting device. The cooled pellets can have solid shapes or hollow shell shapes. Each cooled tablet may contain lithium or beryllium. The pellet cooled with a hollow shell shape can encapsulate a payload. The payload of a cooled pellet may include granules or a porous material. The payload of a cooled pellet may include lithium, lithium deuteride, beryllium, beryllium deuteride, boron, boron nitride, or tungsten.
    The illustrative embodiments also describe pellets which may not be cryogenically cooled before introduction of the pellets into a magnetic confinement melting device. The uncooled pellets may include a hollow shell which encapsulates a payload. The hollow shell of uncooled pellets may include lithium, lithium deuteride, beryllium, beryllium deuteride or boron nitride. The payload of the uncooled pellets may include lithium, lithium deuteride, beryllium, beryllium deuteride, boron, boron nitride, or tungsten.
    With respect to embodiments that use cryogenic processing, examples of suitable pellets may include pellets having metallic exteriors which may include metal having a low atomic number (Z). The representative pellets can optionally be placed inside a cryostat at a low temperature obtained by cryogenics, which causes an increase in the electrical conductivity of the cooled pellets. The cooled pellets can be transferred to a tablet cannon and accelerated to a desired high speed in a magnetic melter such as a tokamak. The high conductivity of the pellets can block the magnetic field of the plasma from the inside of each tablet. This blocking slows down the ablation rate of the pellet, allowing deeper penetration of the pellet and a better adapted spatial profile of the material deposited for an appropriate attenuation of the disruption of the plasma.
    Figure 1 shows a cross section of an illustrative magnetic fusion device (100) where cryogenically cooled pellets (116) are injected into a plasma vessel (115) which is used to spatially confine a magnetized plasma (111) in the form of a torus. As indicated by the center line (Cl) on the left of Figure 1, the plasma vessel (115) can be constructed as a D-shaped torus. The magnetic field region of the plasma core (111) is enclosed by a magnetic cage which includes multiple toroidal field coils (110). The magnetic cage can be formed by a plurality of toroidal field coils (110) which are wound around different parts of the outer surface of the plasma vessel. The magnetic cage is structured to magnetically confine the plasma (111).
    The plasma cross section (111), which forms a torus with an axis of symmetry (Cl), is indicated by the dashed line on the left. The field can be initially excluded from the interior of the representative patch (116) once the patch passes through the magnetic cage. The white region inside the final closed flux surface represents the heart of the plasma (111).
    In some embodiments, a tablet injector (106) is used to inject the illustrative tablets (116) into the plasma (111). For example, the pellet injector (106) may include a single stage light gas cannon. The interaction of the plasma with the ablated material of an illustrative pellet (116) causes the plasma (111) to radiate its thermal energy thereby disseminating it over a large area instead of allowing an uncontrolled loss of thermal energy towards the components facing the surrounding plasma. The plasma (111) can be confined by nested magnetic flux surfaces (112). The same magnetic field that confines the plasma can also be manipulated to control the rate of ablation of the pellet (116).
    FIG. 2 shows an illustrative embodiment in which a magnetic screen (206) of a representative pellet (208) diverts the magnetic field of the plasma (202) around the pellet. The electrons of the plasma (204) follow the magnetic field lines (202), which are excluded, from the interior of the metal pellet (208) by diamagnetic effect. In addition, the heat flux striking the pellet (208) is transported by plasma electrons (204), which are strongly magnetized because they are pinned to the magnetic lines of force (202). Therefore, when these lines of force (202) are diverted around the patch (208), the heat flow will also be diverted around the patch. As a result, the vaporization rate of the pellet can be reduced, thereby allowing deeper penetration of the pellet into the interior of the plasma.
    The physical mechanism that causes the magnetic field lines (202) to be diverted around a metal patch (208) is a diamagnetic phenomenon. The illustrative patch (208) can be either in a massive form or in the form of a hollow shell of suitable geometry such as a spherical hollow shell. The hollow interior of a hollow shell can be filled with a payload material. In some embodiments, the payload may be in the form of weakly compacted granules, for example having a size in the range from 10 to 200 micrometers in some embodiments. In some other embodiments, the payload may be in the form of a porous material.
    In some embodiments, the illustrative pad (208) used for attenuating disruption can include a solid which contains a metal having a weak Z or a light metal such as lithium or beryllium. In some embodiments, the illustrative pad (208) used for mitigation of disruption may include a form of hollow shell in which the outer shell material for the pad is made of either lithium or beryllium. In an illustrative embodiment, the payload inside the hollow shell may contain a metal having a low Z, such as one or more of lithium (Li), lithium deuteride (LiD), beryllium (Be), beryllium deuteride (BeD), boron (B), boron nitride (BN), and tungsten (W).
    In certain embodiments, the electrical conductivity of light metallic elements or having a low Z, such as lithium or beryllium, can be increased from 100 to 1000 times the value at room temperature by cooling these materials to about 10 Kelvin (K) using a suitable cryostat storage device (102). In certain embodiments, a high electrical conductivity can be obtained for metal pellets having a low Z in lithium or in beryllium for attenuation of the disruption in plasmas of magnetic melting device, such as in tokamaks, by cooling the pellets. at 40 K or less using the cryostat storage device (102). Lithium and beryllium are non-magnetic crystalline solid metals for which the temperature dependence of the electrical conductivity results from a diffusion of electron-phonons. In this case, the resistivity p (inverse of the electrical conductivity, p = l / σ) and given by the following Block-Gruneisen formula:
    where p {0) is the residual resistivity at zero temperature due to the scattering of electrons from impurities or crystal defects, and the second term is the temperature dependent part, arising from an electron-phonon interaction , 0d is the Debye temperature, p * is the resistivity at this temperature, and a = 4.225 is a numerical constant. At temperatures well below the Debye temperature, typically around 300-400 K, the resistivity drops considerably as T5 approaches zero.
    FIG. 3 shows a plot of the electrical resistivity as a function of the temperature for a sample of lithium, (Li) (302), and of a sample of beryllium, (Be) (polycrystalline (304); pure crystal (306) ). Figure 3 shows that the electrical conductivity improves considerably during cooling at low temperatures, in particular close to absolute zero, although the resistivity
    residual at zero temperature is apparent. Residual resistivity varies from sample to sample depending on how the sample was prepared and on its purity.
    The high conductivity conferred by the precooling of the pellets can make the diffusion time of the magnetic field in the pellet
    comparable to the penetration of the pellet with speed V
    where σ is the electrical conductivity, μο is the permeability of the free space equal to 4π x 10 ~ 7, rp is the radius of the patch, and a is the minor radius of the plasma.
    Returning to FIG. 1, the tablet (116) can be injected at a certain distance from the plasma (111) where there is no magnetic field. The tablet injector (106) is coupled to the plasma vessel (115). In some embodiments, the tablet injector (106) can inject a tablet (116) into the tablet injection tube (108). One end of the tablet injection tube (108) is connected to the tablet injector (106), and the other end of the tablet injection tube (108) can be coupled to the plasma cell (115) and can extend beyond the toroidal field coils (110) and the stainless steel walls (SST) (114). Injecting a pellet (116) through the pellet injection tube (108) at a distance from the toroidal field coils (110) allows the pellet to have no field inside when it enters the magnetic cage of the magnetic fusion device. Once the wafer (116) is inside the magnetic cage, the field is initially excluded from the interior of the wafer by the circulation of eddy currents on the surface of the wafer. These eddy currents, due to Lenz's law, oppose the diffusion of the magnetic field in the pellet for a certain period of time. The immersion time or the magnetic diffusion time depends on the electrical conductivity of the pellet.
    In some embodiments, the magnetic fusion device includes a cryostat storage device (102) for storing the pellets (116). The cryostat storage device (102) is connected to the pellet injector (106). In some embodiments, the cryostat storage device (102) can be connected to the pellet injector (106) by a pellet transfer device (104). By using the cryostat storage device (102), the electrical conductivity of a pellet is increased by pre-cooling the pellet to an ultra low temperature. In some embodiments, the pellets can be cooled to near absolute zero by immersing the pellets in a bath of liquid helium. In some embodiments, the pellets can be cooled in a liquid helium bath to a temperature less than or equal to 40 Kelvin (K). In a representative embodiment, the pellets can be cooled in a liquid helium bath to about 10 Kelvin (K).
    Figure 1 shows a representative cross-section of a magnetic fusion device (100) showing the plasma (111) with nested magnetic flux surfaces (112) which confine the plasma, and the location of the toroidal magnetic field coils ( 110) which produce the strong magnetic field inside the plasma (leaving the page), with a zero magnetic field outside the cage of toroidal coils. In some embodiments, the pellets (116) are stored in a cryostat storage device (102) and cooled to 40 K before being injected into the plasma (111) at a high speed V. Like the pellets (116 ) are launched in a region without a field, the pellets have no magnetic field inside.
    When the pellets exit the tablet injection tube (108), they are suddenly exposed to the toroidal magnetic field, which is suddenly blocked from inside a tablet by the diamagnetic effect. As the wafer (116) passes through the plasma (111), the field is filtered by the diamagnetic currents flowing over the surface of the wafer, thereby reducing the heat flow of plasma falling onto the surface of the wafer. The characteristic time for the diffusion of the field in the pellet Td is comparable to the time TP for the pellet to reach the central region of the plasma, and it can be around 4 ms for a pellet injected into the magnetic fusion device at a speed about 500 m / s. Without magnetic shielding, the pellet can vaporize completely before reaching the plasma core. The patch always has a small residual resistivity, so that the diffuse field in the patch on the characteristic time scale Td established by the remainder.
    Figures 4A to 4D show simulations of the magnetic configuration surrounding a light metal pellet during representative ablation cooled to 40 K, where t '= t / τ, t = μοστρ2 / π2, rP is the radius of the pellet , and σ is the electrical conductivity of the patch. The simulations presented in FIGS. 4A to 4D use a spherical coordinate system (r, 3, φ) where the center of the patch (400) is located at the origin r = 0. The patch (400) is normalized to a unitary circle r = 1. Figures 4A to 4D actually show projections of the fields and flows on a constant plane φ intersecting the axis of symmetry 3 = 0 which, in the figure, corresponds to the x axis, so well that x = rcosi9 and y = rsin ^. The solid lines drawn from left to right in each figure represent selected magnetic current lines. The annular region between the surface of the patch (400) on the unit circle, and the first line of dashes (402) is the neutral gas portion of the ablation flow. The second line of dashes (404) illustrates the surface where there is a shock, realizing a transition from the purely radial flux along the direction r into a parallel flux along the lines of distorted magnetic field. The region between the first dash line (402) and the second dash line (404) is the ionized ablation flow region.
    In Figure 4A, the arrows show the ablation flow vectors near a pellet during ablation. The diffusion of the field in the pellet, called decay of the eddy currents, is incomplete because of the flow of ablation ionized towards the outside. The field at t = 0 is initially completely excluded from the patch, initially reducing the heat flow to zero. For t> 0, the magnetic field diffuses in the pellet while the pellet travels through the plasma. Due to the outward flow of ablated and ionized gas, the magnetic field inside the pellet can always be reduced even over long periods.
    An additional analysis includes the evolution over time of the magnetic field structure near the pellet, assuming that the currents and the magnetic fields remain axisymmetric, the axis of symmetry being in the direction of the undisturbed magnetic field right to large distance from the pad. In this representative model, the magnetic shielding effect is amplified by the expansion towards the outside of the ablated and ionized gas. The outflow of ablation is relatively undisturbed near the pellet, where its pressure is considerably higher than the magnetic pressure. Thus, near the pellet, the outgoing flow is almost spherically symmetrical and can cross the magnetic field. A flow of ionized gas passing through a magnetic field induces an electromagnetic field (EMF) which, according to Ohm's law, creates an azimuthal current inside the ionized gas. This current flows in the same direction as the eddy current flowing in the pellet. The two currents add up, thus amplifying the screen effect in the immediate vicinity of the patch. As a result of expansion, the ablation pressure decreases with distance from the pellet, until at a certain distance the ablation pressure becomes comparable to magnetic pressure and further expansion is stopped. Beyond this distance, there is little or no current flow when the expansion ceases, and the ionized gas is forced to flow along the magnetic field. In some embodiments, the high electrical conductivity in the pellet and the finished conductivity of the ablation material flowing outward can prolong the diffusion time of the magnetic field in the pellet. The representative model calculates the time for the magnetic field to permeate the patch, and finds that, during the shielding period, the ablation rate of the patch can be significantly reduced, by about 4-6 times in plasma. a magnetic fusion device. As shown in FIGS. 4A to 4D, the strength of the magnetic field is greatly reduced near the surface of the patch together with the heat flux which is directly proportional to the intensity of the field.
    Figure 5 illustrates a representative method (500) of adding representative pellets to a magnetic melting device. The representative method includes a confinement operation (502) where a magnetic cage is used to confine a plasma in a plasma vessel. During the storage operation (504), the representative pellets are stored in a tablet storage device. In an optional transfer operation (506), a tablet transfer device can transfer the tablets from the tablet storage device to a tablet injector. During the injection operation (508), a tablet injector may inject the tablets into the plasma vessel to expose the tablets to the plasma. In some embodiments, a cooling operation can also be performed before the transfer operation (506). The cooling operation may include the use of a cryostat storage device to cool the pellets.
    The illustrative embodiments relate to methods for amplifying the penetration depth of a projectile injected into hot plasma into a plasma confinement device, for example a tokamak plasma device. Injecting dirt particles deep into the plasma can protect the plasma containment device from the severity of plasma disruption events. In certain embodiments, the technology disclosed uses the injection of metallic impurity pellets to achieve controlled extinction of the plasma by radiation of the thermal energy of the plasma over a wide area. The technology disclosed also allows the capacity for deep penetration by engaging the phenomenon of magnetic shielding. Magnetic shielding refers to the strong diamagnetic property of metallic materials when they are cooled to low temperatures obtained by cryogenics, at which the electrical resistance becomes extremely low, thereby increasing the electrical conductivity. The diamagnetic property is not permanent. However, the duration of the effect of the diamagnetic property at low temperatures is such that the confining magnetic field, which confines the plasma, will be excluded from the interior of the pellet during its transit through the plasma, which at in turn temporarily protects the pellet from an intense plasma heat flow.
    Figure 6 shows a cross section of another representative wafer, such as a shell wafer which can be used in the magnetic fusion device without cryogenic treatment. Representative shell pellets can be stored in a storage device and can be sent to the tablet injector using a tablet transfer device which sends the illustrative pellets to the plasma cell. The representative shell pellet (600) includes an outer shell (602) and the payload (604) which may contain densely packed granules or porous material. In some embodiments, a thin shell hollow pellet (600) is filled with a payload (604) such as small granules having a size in the range of 10-200 micrometers. The small granules can be made of a metallic or insulating material, which can serve as a payload for the shell tablet. The shell (602) is ablated while in flight through the hot plasma while the interior payload is shielded from the heat flow of the plasma until, at some specified point deeper inside the plasma, the shell (602) disintegrates, exposing the payload (604) to the plasma. When this occurs, the particles begin to heat and melt or vaporize. In the molten state, the granules may undergo fragmentation into smaller droplets due to the shearing action of a non-uniform surface ablation pressure. Solid tablets do not rupture because the shear force of the tablet material usually exceeds the ablation pressure non-uniformity. As fragmentation into smaller particles greatly increases the surface to volume ratio, the rates of both deceleration by friction and ablation (loss of mass) increase considerably. As a result, the particulate payload substance can be more easily dispersed and trapped inside an irradiated plasma, allowing densification of the plasma.
    In some embodiments, the shell (602) encapsulating the payload (604) may contain a material having a low Z with a desired or adequate structural strength to withstand the accelerating forces in the pellet injection tube without to break up. The materials for the representative shell (602) may for example include light metals such as lithium (Li) or beryllium (Be), or related insulating compounds, such as lithium deuteride (LiD) or beryllium deuteride (BeD), or boron nitride (BN). In certain embodiments, the payload (604) inside the hulls may contain materials similar to those of their hulls, for example comprising lithium (Li), lithium deuteride (LiD), beryllium (Be ), beryllium deuteride (BeD), boron (B), boron nitride (BN), or tungsten (W).
    The chemical compositions for the cooled pellets and the uncooled pellets can be designed or chosen to reduce or minimize the contaminants in the plasma tank. For example, lithium can be used on the interior walls of some plasma tanks to improve the overall performance of the plasma. Representative shells and payloads of representative pellets for such plasma tanks can contain lithium which can mitigate plasma disruption and minimize the introduction of contaminants into the plasma tank. Similarly, for uncooled pellets, the use of light metals such as lithium can also minimize unwanted elements inside the vacuum tank.
    An advantage to using pellets having a weak Z in light metal is that the pellets having a weak Z can be cryogenically cooled to engage the magnetic shielding effect as described in this patent document. An advantage in using pellets comprising insulating compounds is that they allow a higher heat of vaporization and a higher heat of dissociation for the molecular compounds, which reduces the ablation rate and promotes deeper penetration. Another advantage to the use of shells having a low Z is that this use allows the plasma to cool by irradiation more slowly. The theory of resistive magnetohydrodynamics (MHD) warns that care must be taken not to cool the plasma on the magnetic resonance surface q = 2 by persistent impurities. Otherwise, a resistive tear or bend mode can destroy the exterior magnetic surfaces and trigger an inwardly propagating cooling front. Therefore, cooling from the inside to the outside is preferred to cooling from the outside to the inside because the central region of the plasma has fewer unstable or rational magnetic surfaces than the outside regions.
    The ablated and ionized particles cause the plasma to undergo thermal collapse caused by irradiation in the deeper regions of the plasma. The particles can also dissipate the decoupled electrons, by braking the decoupled electrons which can amplify, by an avalanche chain reaction, in large and dangerous decoupled electron currents.
    Based on simulations, when the plasma is cooled from melting temperatures (e.g. around 20,000 eV) to lower temperatures (e.g. around 30 to 100 eV), the initially densely packed particles can still quickly break up into smaller clusters which then crack recursively to become smaller and smaller, until individual dust particles eventually become exposed to the plasma. An estimate of the dislocation time can be given as follows. The time to cause the first fission of the initial payload mass is roughly rro = Ro / co where Ro is the initial radius of the pellet and
    is the time of arrival of the sound where po is the surface ablation pressure exerted on the initial charge mass, p is the density of the mass of dust, including the empty space, and a <1 is a coefficient of asymmetry. After n fissions, the number of densely packed clumps of particles, or blobs ("zone form" in French), will be 2n. It is further assumed that: (1) the mass is retained (blob ablation neglected); (2) each blob has a spherical shape; and (3) p and a for all the blobs remain constant. Since the ablation pressure is scaled with the blob radius in the form p oc Rr1 / 3, the time for the original payload to disperse in this way becomes
    Considering that the initial payload mass is the diameter of the pellet, for example, D = 1.5 cm, and p ~ 1 g / cm3, the ablation pressure in a plasma cooled to 100 eV is approximately 1 MPa, which gives a fragmentation time of approximately 1 ms, which is sufficiently short if the speed of the pellet is <500 m / s.
    The penetration of the individual dispersed dust particles will be limited both by deceleration and by loss of mass (ablation). The faster vaporization rate is due to the extremely small particle size; the lifetime, which is proportional to TVie ce D3 / G oc d5 / 3 (where D and G are the particle size and the mass ablation rate respectively), ensures that the isolated granules will be completely ablated inside of a hot plasma of 30 to 100 eV rather than hitting the opposite wall. The particles are also contained inside the plasma by stopping the
    friction. In a certain embodiment, the size of the fine grains or dust may be about 10 microns, which is much less than the Debye length of the ambient plasma. Then, the Coulomb braking force on an isolated grain of dust can be calculated from the processing limited to orbital motion (OML). It is assumed that the speed of an initial dust particle relative to the plasma is equal to the speed of the original Vpastnie / pellet of approximately 500 m / s. As Vpastiiie is much lower than the thermal velocity of the ions and electrons even for a thermally collapsed plasma of 10 to 100 eV, the coulombian braking force on a moving dust particle is largely due to its interaction with plasma ions. background. The stopping time r of a grain of dust moving relative to the background ions is therefore analogous to the time of deceleration of a fast ionic test particle (MeV) moving through a plasma of hot electrons, in the sense that the scale is similar: τ oc T3 / 2 / Zd2, where T is the temperature of the target particles and Zd is the charge on the grain of dust (test particle). The 3/2 temperature scale is familiar, and it indicates that the stopping time shortens when the plasma cools by irradiation, except in the case of a grain of dust where it adopts a potential, the floating potential, so that its charge Zd also depends on the temperature of the plasma T. If all of this is combined, the deceleration time in a hydrogenated plasma is indicated below:
    where n (nr3), T (eV) and M (uma) are respectively the ion density, the temperature, and the ion mass, of the plasma, pd (kg / m3) is the density of the material in the grains of dust, r (m) is the grain radius, and ψ ~ 2-5 is the normalized floating potential at the temperature of the ions, and ΙηΛ of about 10 is the logaromb of Coulomb. For example, if we consider fusion parameters such as T = 100 eV and η = 1020 itr3, we obtain r = 0.6 ms, and therefore, in certain embodiments, a stopping distance for a
    pad speed of about 500 m / s can be 30 cm. Therefore, any unblasted dust particles can be easily trapped inside the plasma with a minor radius of 0.66 m.
    Although this patent document contains many specifics, these should not be viewed as limitations on the scope of any invention or what can be protected, but rather as descriptions of features which may be specific to them. particular embodiments of particular inventions. Certain features which are described in this patent document in the context of separate embodiments can also be applied in combination in a single embodiment. Conversely, various features which are described in the context of a single embodiment can also be implemented in multiple embodiments, separately or in any suitable sub-combination. In addition, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features of a claimed combination may, in some cases, be derived from the combination, and the protected combination may relate to a sub-combination or a variant of a sub-combination.
    Similarly, although operations are described in the drawings in a particular order, this should not be understood as requiring that these operations be carried out in the particular order indicated or in successive order, or that all the operations illustrated are carried out , so that desirable results are obtained. In addition, the separation of various components of a system in the embodiments described in this patent document should not be understood as requiring such separation in all embodiments.
    Only a few examples and implementations are described, and other implementations, improvements, and variations can be made based on what is described and illustrated in this patent document.
    权利要求:
    Claims (18)
    [1" id="c-fr-0001]
    1. A melting device comprising: a plasma tank (115) structured so as to include a hollow interior for confining a plasma; a plurality of toroidal field coils (110) wound around different parts of an outer surface of the plasma vessel, the plurality of toroidal field coils being configured to magnetically confine the plasma within the plasma vessel; a storage device (102) which stores pellets; and a tablet injector (106) positioned to receive pellets from the storage device and operable to inject the pellets into the plasma vessel.
    [2" id="c-fr-0002]
    2. The melting device according to claim 1, wherein the storage device (102) is a cryostat storage device which stores and cools the pellets, and where the pellets have metallic exteriors.
    [3" id="c-fr-0003]
    3. A melting device according to claim 2, wherein the cryostat storage device (102) is configured to cool the plurality of pellets to a temperature less than or equal to 40 Kelvin (K).
    [4" id="c-fr-0004]
    4. The melting device according to claim 2, wherein the cryostat storage device (102) is configured to cool the plurality of pellets to a temperature of 10 Kelvin (K).
    [5" id="c-fr-0005]
    5. A melting device according to any one of claims 1 to 4, wherein the plasma vessel (115) has the shape of a D-shaped torus.
    [6" id="c-fr-0006]
    6. A fusion device according to any one of claims 1 to 5, wherein the pellet injector (106) contains a single stage light gas cannon.
    [7" id="c-fr-0007]
    7. A method for attenuating the disruption of a plasma, comprising: the magnetic confinement of a plasma in a plasma tank t the storage of pellets; and injecting the pellets stored in the plasma tank.
    [8" id="c-fr-0008]
    8. The method of claim 7, further comprising cooling the pellets stored to a temperature less than or equal to 40 Kelvin (K).
    [9" id="c-fr-0009]
    9. The method of claim 8, wherein the stored pellets are cooled to a temperature of about 10 Kelvin (K).
    [10" id="c-fr-0010]
    10. The method of claim 8, comprising the use of solid pellets as pellets.
    [11" id="c-fr-0011]
    11. The method of claim 8, comprising the use of hollow shell pellets as pellets.
    [12" id="c-fr-0012]
    12. The method of claim 11, wherein each hollow shell pellet encapsulates a payload.
    [13" id="c-fr-0013]
    13. The method of claim 12, wherein the payload comprises granules or a porous material.
    [14" id="c-fr-0014]
    14. The method of claim 12, wherein the payload comprises lithium, lithium deuteride, beryllium, beryllium deuteride, boron, boron nitride, or tungsten.
    [15" id="c-fr-0015]
    15. The method of claim 8, wherein each tablet contains lithium or beryllium.
    [16" id="c-fr-0016]
    16. The method of claim 7, comprising the use, as a pellet, of a hollow shell encapsulating a payload.
    [17" id="c-fr-0017]
    17. The method of claim 16, wherein the hollow shell comprises lithium, lithium deuteride, beryllium, lithium deuteride, or boron nitride.
    [18" id="c-fr-0018]
    18. The method of claim 16, wherein the payload comprises lithium, lithium deuteride, beryllium, lithium deuteride, boron, boron nitride, or tungsten.
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    同族专利:
    公开号 | 公开日
    CN109949947A|2019-06-28|
    US20190198182A1|2019-06-27|
    US11087891B2|2021-08-10|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US3668067A|1969-10-16|1972-06-06|Atomic Energy Commission|Polygonal astron reactor for producing controlled fusion reactions|
    US3953617A|1974-01-28|1976-04-27|The United States Of America As Represented By The United States Energy Research & Development Administration|Method of producing encapsulated thermonuclear fuel particles|
    US7831008B2|2005-10-21|2010-11-09|General Atomics|Microwave-powered pellet accelerator|CN110767325B|2019-10-31|2021-04-06|中国科学院合肥物质科学研究院|Method for realizing fusion reactor plasma core charging by using sandwich shot|
    RU2736311C1|2019-12-17|2020-11-13|Виктор Сергеевич Клёнов|Device for charged particles retention|
    法律状态:
    2019-10-14| PLFP| Fee payment|Year of fee payment: 2 |
    2020-10-13| PLFP| Fee payment|Year of fee payment: 3 |
    2021-09-30| PLFP| Fee payment|Year of fee payment: 4 |
    2021-10-15| PLSC| Publication of the preliminary search report|Effective date: 20211015 |
    优先权:
    申请号 | 申请日 | 专利标题
    US15/851,542|2017-12-21|
    US15/851,542|US11087891B2|2017-12-21|2017-12-21|Methods and apparatus for mitigating plasma disruption in fusion devices|
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