JPS58100392A - Plasma unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Description to which the Invention Pertains The present invention is directed to a plasma device that allows plasma to be confined for a long time using an open magnetic field.

Conventional technology and its problems It is well known that when confining plasma using an open magnetic field, it is necessary to increase the plasma confinement time in fusion reactors. In plasma equipment as well, by increasing the confinement time, the power consumption of the plasma generator can be reduced, the density of the plasma can be made more uniform, and the heat input to the solid wall surrounding the plasma can be reduced. Great effects can be obtained. Plugging at the open end is required for plasma confinement with an open magnetic field and rounding to increase the confinement time. This means that for example CoGormexano:
Reduction of Losses in Op
@n-EndedMagnetic Traps;
Nucjear Fusion, 1G ('79)
.

8.1083 and other documents.

There are two types of prying, one using high frequency and one using an electrostatic field.The other method using an electrostatic field includes the electrode method using an electrode, and the bipolar potential confinement using a tandem off-type magnetic field.
All of these are in the research notice. This electrode method includes a Vh9 electromagnetic trap that uses electrostatic plugs consisting of an anode and a cathode at the cusp magnetic field point and line cusp. 1st
@ is the original diagram of the electromagnetic trap, and is based on documents T, J, and DoJan.
,B,L,8tani-field and J,M,
Larsen:PIasma Potentlij 1
! 1ejectroaaticaJjy pjugg
ed cusp@and m1rrors: The P
hycics of i'7uids, 18('75
) e 10. It was published in 1583.

The code (1) in 1 is a set of two coils that are wound axially symmetrically in a zmot winding, forming a cusp magnetic field. (2) is a hollow cylindrical OII % arranged at the point cusp.

(3) is a hollow cylindrical cathode arranged at the point cusp, 14) is an annular anode arranged at the line cusp and has 92111 sets, and (5) is a set of 2 annular anodes arranged at the line cusp. It is a cathode. A vacuum container (not shown) is provided in the dead space sandwiched between the two coils (1) and in the space inside the coil (1), and this vacuum container is filled with gas to become plasma. , nine electrons are emitted from an electron gun (not shown) on at least one side of the cathode (3) opposite the anode (2), and pass through the cathode (3) and the anode (2) to create a vacuum (not shown). The zero dotted line (6), which moves inside the container and ionizes the filled gas to form plasma, zeros the potential of the cathode (3) and the cathode (5), which indicates the boundary of the space where Gutsuzu i exists. , when the potentials of the anode (2) and the anode (4) are φA, the spatial potential φ near the Z axis is distributed as shown in FIG. The potential φ of the space where the pu9jC ma exists, and O<φe and φmu. Both IIK in the space where the plasma exists are inside the anode (2) (a mountain of potential is formed and the potential becomes φe + φi at the highest potential. The charge of the ions is Ze, and the charge of the electrons is - When e and Oitomo, ions whose energy is smaller than Zυi and whose kinetic energy is
Electrons smaller than φe cannot escape from the space where plug i exists in the direction of the magnetic field, and ions are reflected and returned to the plasma (as shown by arrow (8)), and ions are reflected as shown by arrow (8). , TI is the ion temperature of the plasma.

If electron @ degree is Tc, it is 1! , φheavy'')) k'l'i /7.e, φe >> kTe
/e - (1) (The effect of the conventional electromagnetic trap is that it is possible to ply the plasma at one emission point, and the confinement time can be significantly improved.

- This electromagnetic trap tc 4 s There are six problems as follows: t@2 As shown in Figure 2, the space potential inside the anode (2) reaches a maximum of φi+φC.

Δφ=φmuichi (φi+φe) ・・・・・・・
...12) The difference Δφ between the @polar potential and the space potential does not become zero, and Δφ>O. The reason why Δφ is formed is that electrons are captured inside the anode to form a group of electrons, and an electrostatic field is formed by the space charge created by this group of electrons. Δφ is a function of the distance r from the Z-axis, which can be expressed as iΔφ=Δφ(r). Taking into account the direction of the electric field created by the electron group, it can be seen that θ(Δφ) on the Z-axis. Since the r component of the electric field is O, Δφ has the maximum value Δφmax Δφmax"'
Take Δφ(0). Therefore, within the anode, the potential on the Z axis is expressed by the formula (2)%
φi and φe are determined by the particle class equilibrium of the plasma, etc., but they are approximately the same size. In other words, r=Q, φi〜φe〜o, r=o...
...(3) It is known that equation (1) does not hold true.

However, in most parts of the anode, equation (1) holds true, and equation (3
) holds only for a very small portion of r, so the electromagnetic trap has a large effect of increasing the plasma confinement time of the electrostatic plug, but as equation (3) holds when r~0, a loss aperture is created in the electrostatic plug. The effect of increasing plasma confinement time is limited because the plasma leaks through this formation.

purpose of invention The present invention has been made in light of these circumstances.

The aim is to provide an electrostatic plug with no loss aperture (to realize an open-system plasma device that can confine high-temperature, high-density plasma and significantly increase the confinement time). That's true.

The cloud of the invention is provided adjacent to the limiter that determines the plasma boundary and its potential to suppress the inflow of electrons into the anode.

The axis of the hollow part of the anode adjacent to the first cathode is isolated from the part where plasma electrons enter, forming an electrostatic plug with no loss aperture, making it possible to confine high-temperature, high-density plasma for a long time. did.

Embodiment of the Invention FIG. 3 is a configuration diagram of a plasma apparatus showing an embodiment of the invention. A set of two coils n) are axially symmetrical (wound) around the Z-axis, and together with an excitation power source (not shown) constitute a device that generates a kind of cusp magnetic field of an open system magnetic field that accommodates plasma.C4) is a cusp magnetic field. A set of 92 annular anodes arranged at the line cusp, which is one of the open ends of the magnetic field, (
5) is a set of two annular cathodes disposed at the line cusp, forming an electrostatic plug that forms an electric field having a non-zero component parallel to the direction of the magnetic field at the line cusp;
Kukumon is held between Mukuro Coil (1) and said Coil (1).
A vacuum vessel (not shown) is arranged in the internal space of the plasma chamber, and a limiter (9) defining a plasma boundary surface (6) is accommodated in the vacuum vessel. Two Qt Tries (9)
are arranged at the point cusps, which are the two open ends of the cusp magnetic field, and the direction of the magnetic field (through it and having a hollow part,
Surrounds the plasma in the cough hollow. The potential φp of the space where plasma exists is controlled by the -first potential φl. That is, since the potential difference between the plasma and the sheath (9), that is, the sheath voltage φS, is determined by the conduction of plasma electrons and ions through the sheath existing between the slot (9) and the plasma, φp=φj+φS...・Song (4) K
After a few seconds, φp is determined.

The reference numeral 0 in the figure indicates the wrinkle 17, the first cathode 01 having a hollow part arranged adjacent to the first cathode (9) and having a hollow part through which nine lines of magnetic force pass. An anode, which is arranged adjacent to the cathode (9) and opposite (IIIK) and has a hollow part through which the nine magnetic field lines pass through the hollow part of the crease (9). A round plate-shaped second cathode is arranged so as to be in contact with the opposite side of the anode a to the cathode and to cover the opening of the anode a, and includes a second cathode, a first cathode QO, an anode αυ, and a second cathode α■. constitutes an electrostatic plug, and in this embodiment, an electrostatic plug is provided at each of the two point cusps that are the open ends of the cusp magnetic field, and the silent plug is arranged in the direction of the magnetic field as described below. forms an electric field with a nonzero component parallel to .

Figure 4 shows the structure and operation of the main parts of the embodiment shown in Figure 3, where (a) is a diagram of the electrostatic plug configuration, and (b) shows the dependence of space potential φ(r, z) on r. Diagram (C) is a diagram showing the two-dimensional dependence of the space potential φ(r,z).

Anode a1 has electricity 1i! (A voltage of 14K is applied to the stain, and a potential φkl is applied to the first cathode (11) by the power supply.)

A dynamic potential φ of 2 is applied to the second cathode a by the power source αe, and between each potential, 4kg<φkt<0<φa .
- The relationship (5) holds true. The limiter (9) is grounded, and plasma (
1s is in contact. Potential φ of the space where plasma exists
From (4), p is φp=φl. For each potential -, φg
, the absolute value of φ1 is set large so that the electrostatic plug works effectively, so 1φp1 (21.φ for 1φkllelφ). That is, referring to %(5), 4kg<φkl<φp. φa...
・・田) is established. The axis of the hollow part of the anode αυ is +7
<Yu (9)O Nine lines of magnetic force pass through the hollow part and are located outside the magnetic flux tube formed in the hollow part of the anode aυ, and intersect with the flange-shaped part of the first cathode axis.

Effects of the Invention FIG. 4(a) shows the K embodiment thus constructed and shows the action of the electrostatic plug (II) and the effect of the invention in FIG. 4(Φ) and (
To explain with reference to C), in the hollow part of the anode, like the inside of the anode of an electrostatic plug at the point cusp of an electromagnetic trap, electrons are captured and form an electron group, and a space charge created by the scissors electrons is generated. The electrostatic plug of the present invention, in which an electric field is formed, is different from the electrostatic plug of the electromagnetic trap at the point cusp of the electromagnetic trap.
In the electrostatic plug according to the present IJIK, since the anode does not pass through the hollow part of the anode's hollow part or the hollow part of the axial center beam (9), the magnetic field lines passing through the vicinity of the electrostatic book cover (the space where plasma exists) , the hollow part of the anode (1*) exists only where the distance τ from its axis is r = Q.On the other hand, in the electrostatic bladder at the point cusp of the electromagnetic trap, the plasma and the existing space The lines of magnetic force that pass through also exist at r=Q in the hollow part of the anode.In the electrostatic plug of the present invention, as well as the electrostatic plug at the point cusp of the electromagnetic trap, there is a space in the tI! part in the middle of one anode. As shown in FIG. 4 (rb), the potential φ1 is at its minimum on its axis, and the potential φklK of the second cathode is approximately equal.Here, the potential drop between the electron group and the first cathode is ignored. On the other hand, p2zu i
Potential distribution φ3 in the hollow part of the limiter (9) surrounding the brocade
As shown in FIG. 4(b), is φp in the space where the plug t1 exists, and is 0 at the inner wall of the limiter. φp takes a negative value due to the difference in the Rahma radius of ions and electrons. Ions and electrons ejected from plasma AS almost form magnetic lines of force? 8-), but the lines of magnetic force move along the anode's hollow m1 (1
1, R1<r<RsK. r == R1.

(R1+B-s)/2 == Space potential of electrostatic plug I at R2eRs φ(Rlg), φ(R'2
1") #φ(R3,z) is shown in FIG. 4(C). They are all at a positive high potential KTo with respect to φpK in the hollow part and inner surface of the anode. Since the lowest potential in the hollow part a is φ(31,z), all the magnetic field lines KfEi passing through the plasma are similar to those shown in Figure 2, creating a potential barrier for both ions and electrons. (1) The electrostatic plug of the plasma device of the present invention does not have a loss feature that exists in the electrostatic plug at the point cusp of the electromagnetic trap. This is the first effect of the present invention, and as the plasma confinement time is greatly increased by this seedling, an open system plasma device can be realized.

Next, the action of the first cathode Q and the effect on plasma confinement will be explained. When there is no space charge there, the potential of the hollow part of the second cathode becomes a tortoise-high potential which is approximately equal to 1 to the potential φ of the first cathode. In reality, plasma electrons cannot reach the high-potential part of the scissor because they are reflected, but they can reach it after being accelerated by the plasma ion beam. Assuming that there is no space charge, the potential at (to) takes a value close to OK than the potential at nine. Some of the ions flying through the hollow space (4) are captured and form an ion group. When the particle loss of the Mukuro ion group is small,
The ion density increases and its maximum value reaches the potential φpK of the space where plasma Miro exists, but it does not exceed φp. In this case, the potential distribution in the hollow part of the first cathode is shown in Figure 4 (b). ) is φ2. The good electrons ejected from the plasma are exposed to the potential barrier φ created by the hollow part of the first cathode.
It encounters p-6, and most of it is reflected here and plugs! A small amount of the residue passes through the hollow part of the first cathode and reaches the hollow part (IIK) of the anode, and is reflected by the potential barrier created by the second cathode. and is eventually returned to plasma.

The density of the electron group formed in the hollow part of the anode (therefore,
The temperature and density of plasma that can be confined are determined.

It is impossible to plug high-temperature, high-density plasma directly between the hollow part of the anode and only one cathode.As a result of using the first cathode in the present invention, the number of plasma electrons flying into the hollow part of the anode is significantly reduced. It is now possible to confine plasma at a high temperature. This is the second effect of the present invention.

APPLICATION OF THE INVENTION The present invention relates to an open system plasma device. In the embodiment, nine plasma devices were explained using a cusp magnetic field, but the magnetic field is not limited to a cusp (not limited to an open system where the present invention can be applied; for example, the present invention can be applied to a uniform magnetic field, a mirror magnetic field, etc.). However, the application of the plasma device is not limited; for example, it can be applied to a fusion reactor, a surface processing/processing m% welding, an ion source, and the like.

[Brief explanation of the drawing]

Figure 111 is a ring diagram of an electromagnetic trap, Figure 2 is a miniature diagram showing the distribution of space potential near the two wheels of an electromagnetic trap, @311 is a configuration diagram of a plasma device showing an embodiment of the present invention, and Figure 4 is a diagram of the configuration of a plasma device showing an embodiment of the present invention. 3 shows the configuration and operation of the main parts of the embodiment shown in Figure 3, where (a) is a diagram showing the electrostatic plug configuration, (b) is a diagram showing the r dependence of the space potential, and (C) is a diagram showing the Z dependence of the space potential. It is a microcosm of dependence. (1)...Coil, (2), +41, (iυ...
・Anode, +3), τ5)...Cathode, +9)...Q
t, [1...first cathode, 11a...second cathode,
I...Electrostatic plug, on, flag, a...Electric St%
Ri...Plasma, (II...Hollow part of anode αυ,
(2G...Hollow part of the fourth cathode.

Claims (1)

[Claims] A device for generating an open-system magnetic field that accommodates plasma, a means for controlling the electric potential of a space where the plasma exists, and In a plasma device comprising an electrostatic plug that establishes an electric field with parallel non-zero components. At least one of the electrostatic plugs is disposed adjacent to a limiter and a wrinkling limiter of the open system magnetic field that have a hollow portion penetrating in the direction of the magnetic field and surround the plasma, and are arranged to protect the hollow portion of the limiter. A first cathode having a hollow part through which nine magnetic power lines pass through, and a hollow part which is disposed in contact with the opposite side of the limiter on the opposite side of the limiter and has a hollow part through which nine magnetic power lines pass through. a second cathode (disposed adjacent to the opposite side of the first cathode of #1lIIIA and covering the opening thereof;
The electric potential that serves the anode is equipped with means for applying a potential lower than the limiter potential to the two cathodes, and the axis of the hollow part of the anode passes through the hollow part of the Yang