JPS58100397A - 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 Field of the Invention The present invention relates to a plasma device that enables plasma confinement using an open magnetic field.

Prior art and its problems It is well known that when plasma is confined in an open magnetic field, it is necessary to lengthen the plasma confinement time due to coalescence. In the plasma equipment used, the power consumption of the plasma generator can be reduced by increasing the confinement time, and by increasing the density of the plasma, the heat input to the solid wall surrounding the plasma can be reduced. Great effects can be obtained, such as reducing

Plugging at the open end is required for rounding to increase the confinement time in plasma confinement with an open system magnetic field. This is true for example, C8 Gormaxano
:R+education or losses
En Op@n-FSndedMagn*tic'
I'raps; NuclaarFusioa, 19('
79), 8°1085, etc.

There are two types of plugging: those using high frequency waves and those using electrostatic fields. Those using electrostatic fields include the electrode method using electrodes, and bipolar potential confinement using tandem mirror magnetic fields.
All of these are still under research. This electrode method includes an electromagnetic trap using an anode and an electrostatic plug consisting of an anode at the point and line cusp of the cusp magnetic field. Figure 1 shows the principle of an electromagnetic trap, and is based on the literature T, J, Dojan.
, B, L.

8-tanifiajd and J, M, mr.
sen:Pjasma Pot*ntia/in
gJectr@5tattcajjy Pjugge
d Cu5p@Mirrors:Th@Phyc
ic@of FJuids, 1B ('75'), 1
It was published in 0.1383.

The reference numeral (1) in the figure indicates a set of two coils, which are wound axially symmetrically in a biaxial manner to form a cusp magnetic field. (2) is a round hollow cylindrical l1ilfi arranged at the point cusp, (
3) is a hollow cylindrical cathode located at the point cusp;
(4) is a set of two annular I arranged on the line cusp.
II, (5) is a set of two Jll-shaped single poles arranged at the line cusp. These two coils (1)
A vacuum container (not shown) is arranged in the space inside the KM spacecraft and the coil (1), and this vacuum container is filled with gas to become plasma, and at least one of the anodes of the cathode (3) An electron gun (not shown) is installed on the opposite side of (2), and the Kuryuko emitted from this electron gun passes through the anode (3) and the anode 1g (2) and moves inside the vacuum container (not shown). , the zero dotted line (6), where plasma is formed by ionizing the filled gas, indicates the boundary of the space where the plasma exists. When the potentials of the anode s4 and the anode s4 are set to φ, the spatial potential φ near the two axes is distributed as shown in Figure 2. The potential of the space where the plasma exists is φe, which is 0×φ6×φum. On both sides of the space where plasma exists, positive [
A potential peak is formed inside (2), and the potential becomes φ6+φi at the highest potential point. When the electric charge of an ion is 2@ and the electric charge of an electron is -C, an ion whose energy is smaller than zeφi and a kinetic energy eφ. Smaller electrons cannot escape from the space where the plasma exists in the direction of the magnetic field, and ions are reflected back into the plasma as shown by arrow (7) and electrons are reflected as shown by arrow (8). That is, if the plasma ion temperature is Ti#IK temperature T, then
φt >> kTl /Ze, φ, >>kT, /e
, −(1) allows plugging at the open end of the plasma, and reduces the confinement time by RK
What can be improved is the effectiveness of conventional electromagnetic traps.

This electromagnetic trap also has a problem similar to the first order. 1g
As shown in Figure 2, the space potential inside the anode (2) is an ant-sized φ1+φ. However, Δφ=φmu−(φi+φ.) ...(
The difference Δφ between the anode potential and the space potential given in 2) does not become zero, and Δφ>0. The field is formed because electrons are captured inside the anode and form a group of electrons, and the space charge created by these ζ particles forms an electric field. 4 is 2
The distance from the axis is a ro function, and it is likely that Δφ = Δφ ( ). Considering the direction of the electric field created by the electron group, 11 buttons < 0, r > O a.

Since the r component of the electric field is 0 on the 02 axis, Δφ has a maximum value Δφ □ at r=Q.

Δφmax"Δφ(0). Therefore, the potential on the Z axis within the anode is φi+φ.=φ□−Δφmax from equation (2). φi and 10 are determined by the balance of the number of particles in the plasma, etc. , approximately the same size, φ5 to φ. Therefore, φi to φ on the Z axis.

～Toφe−ΔφtELIK) In the electromagnetic trap, Δφ01. As a result, x becomes very large and almost equal to φm, so that on two axes, that is, at "=0, φi~φe~o, r=o...(
3), and it is known that equation (1) does not hold.

However, in the large part inside the anode, equation (1) holds true, and equation 1 (3
) holds only for a very small portion of Ivh, so the effect of increasing the plasma confinement time of the Hiro electrostatic plug using an electromagnetic trap is large. The effectiveness of increasing plasma confinement time is limited because an aperture is formed through which the plasma leaks.

OBJECTS OF THE INVENTION The present invention has been made in view of the above circumstances, and its purpose is to provide an electrostatic plug without loss aperture, thereby creating an open system plasma that can confine high-temperature, high-density plasma for a long time. We are in the process of providing equipment.

aS of the invention The present invention consists of an anode that passes through the plasma or mixes with lines of magnetic force in contact therewith, an anode that surrounds it without mixing with the lines of magnetic force, and a control that extends into the internal space of Kll-Ko without mixing with the lines of magnetic force. By forming an electrostatic plug with an electrode in a plasma device using an open system magnetic field, we can achieve the purpose of realizing an electrostatic plug that has no loss aperture and has very little electron flow into the control electrode. Nine.

Embodiment #I3 of the invention is a configuration diagram of a plasma apparatus showing an embodiment of the invention. The coils (1) of the 2 control groups are wound axially symmetrically around z@O, and the power supply (not shown) and 4K.

f7 generates a kind of cusp magnetic field in the open system magnetic field that accommodates the plasma! & Configure the location. (4) are two pieces arranged at one line cusp, which is one of the open ends of the cusp magnetic field.
The ring-shaped 1111i, (5) is a 211-pair of ring-shaped cathodes arranged at the line cusp, and constitutes an electrostatic plug that forms an electric field with a non-zero component parallel to the direction of the magnetic field at the line cusp. , a vacuum vessel (not shown) is disposed in the space between the two control sets of coils +1) and the space inside the skeleton coil 11).

The cough vacuum container accommodates a third wall (not shown) that defines the boundary (6) of the space where plasma exists. The potential φ of the space where plasma exists is the potential φ of the third wall. controlled by That is, the conduction of plasma electrons and ions through the sheath that exists between the bell and the plasma determines the potential difference between the plasma and the blind wall, that is, the sheath voltage φ.

S=φ. +φ, ...(4) determines φp. The plug is an electrostatic plug placed at the point cusp that is the open end of the magnetic field, and forms an electric field with a non-zero component parallel to the direction of the magnetic field, as described later. 〇4, which is used in both po-ind cusps, is a plate-shaped cathode, and the surface of the plate is connected to the lines of magnetic force.
The magnetic force passing through the space where the plasma exists and the lines of magnetic force circumscribing the space where the plasma exists all intersect with the cathode. (9) is an anode, which is disposed between 11 and the plasma, and surrounds both the magnetic lines of force passing through the space where the plasma exists and the lines of magnetic force circumscribing the space where the plasma exists. 1llk Ii A through hole is drilled in the part of the trout that does not intersect with the above magnetic field lines, and the control electrode αυ passes through the trout through hole without contacting t*ii, and the control electrode Iiaυ is connected to the internal space of II [i 19) extends to

84m is a haze showing the action of #l3allK, which shows the action of the main part o, (C) is a diagram showing the r dependence of the space potential φ(t, φ, is given, and the potential φk is given to the dust lIa by the electric potential #UK.@For each potential m, φk<0<φg<φ1...
The relationship (5) holds true. The trout is grounded with JI + bell) Plasma is in contact with the inside of the fish via the sheath Qη.The potential φ of the space where 0 plasma exists is φ,
From equation (4), -9=φ. Each potential φa w d
The absolute value of l#φ is set large so that the electrostatic plug works effectively, so 1φp l << Iφ
11. Referring to o(5), *, , *, -, φk〈φ, kuφ, kuφ, ...(6)
holds true. A through hole a is formed in the cathode Ql, and the control battery I passes through the through hole utt without contacting the cough cathode one, and extends through the hollow part CIIK of the anode (9).

The electrostatic plug 00 shown in FIG. Similar to the inside of the anode of an electrostatic plug at the point cusp of an electromagnetic trap, electrons are captured to form an electron group, and an electric field is formed by the space charge created by the electrons. The point cusp of an electromagnetic trap differs from an electrostatic plug in 1.
In the electrostatic plug of the present invention, the hollow part of the anode @IIK
Density line control electrode of 4 electron groups @ID potential φg
and the potential of the anode (9) -1, so that the space potential in the hollow part of the anode (ilK) φ(r,z) = φ
By controlling ('*''i), like an electrostatic plug at the point cusp of an electromagnetic trap, (3) the potential field at r ~ 0 decreases as shown in 2, and a loss aperture is thereby formed. In the electrostatic plug according to the present invention, the space potential in the hollow part (2) of the scissor anode that easily attracts harmful birds -φ
1 and the scissors control electrode is at r=~.

It is. Here, φ0 is the minimum value of φ(r, sl) and is 1 W
It is the potential at O, and the precondition of φ0>φ is 0 because Il#electric@I controls the space potential. This is a Qin matter.

The spatial potential distribution φ(r, gl) is shown in Figure II4 (C).

In the hollow part (7) of the anode, the electric field is directed in the r direction, so the electron group drifts around two axes. Even if changes, the potential distribution returns to that shown in equation (7) due to the action of control electrode all.◇When equation (7) holds true.

φ(BIIl, J) = φ,
-+8), if the electron density increases, the electric field will become stronger and become φg. At this potential, the electron beam rapidly collides with the control electrode and is absorbed, so (8
) The electron density continues to decrease until the equation (8) is established, and the potential eventually returns to the equation (8). Nine, if the electron density decreases, φ
(Blgm ” 1) > φg, and the electrons cannot collide with the control electrode.The electron density has a strong tendency to increase (due to electrons supplied from the plasma, etc.), and as the electron density increases, the potential eventually becomes Equation (8). Returning to 0, that is, due to the action of the space potential line and the control electrode, the distribution shown in equation (7)
kept stable.

Next, the potential of the space where plasma α exists - (r, x) =
Consider φ°''(r, xl).In a space where plasma (110) exists, the electric field is very weak, so the potential φ('',
can be considered to be constant. That is, φ(r, odor)=φ.

As described above, the sheath voltages φ and φ are equal◎, that is, φ,=φ. The sheath voltage φ takes a negative value due to the difference in the Rahma diameter of the ions and electrons that make up the plasma, and its magnitude is larger than the magnitude of the potential applied to each electrode of the electrostatic plug, 1φkl e dfle411. The salary is small. Namely.

1φp1 (1φkl, φ1.φ1...
(9) Potential distribution φ in the space where 0 plasma exists
('-"2> 4 *Figure 4 (OK shown 0 4th
11 IC groaning has a potential φ('@”)s anode (9
) on a straight line that is in contact with the inner surface and parallel to the two axes φ(R,,l
) and the potential −(machi, x) on a straight line parallel to the inner surface KIiLZ axis of the first eleventh mouse are shown. φ0=φ(0, 1,
) is the minimum value of φ(r, gl), so all r
As shown in the 1s2 diagram, a potential barrier is formed for both ions and electrons, and the hollow lance of the anode is
It can be seen that 1cJIJK does not have a loss aperture. Plasma resides inside IIaII, positive f
The 0 ion, which is formed in the hollow part (7) of & and is isolated from the electron group, faces the potential barrier (-(r,'z1)-φ
, dZ, and the electron is reflected by the potential barrier φ, −
It is reflected by φkK. The relationship corresponding to (1), φo-4p''>> kTi/Z6, φ, -φk>
> kT, /* ・06 holds because (9) holds,
#Easy K11lll0 Therefore, an open system plasma device that can significantly increase the plasma confinement time is l! Clouded with maple.

Next, we will discuss the effect of the invention that the plasma device of the present invention can confine even high-temperature, high-density plasma.From the plasma aFj existing inside the boundary (6) indicated by the 0 point -, there is no direct contact with the electrostatic plug. 0 where ions and electrons are ejected
ion is a potential barrier (-(r, gl)-φ,)
z, the electrons are reflected back to the plasma before reaching the anode's hollow S(to)K.
It is reflected by φk and becomes a sun cage again.

Penetrating the hollow part (end) and returning to the plasma ＠This movement of electrons does not cross the magnetic field lines in the ``direction'' because the zero-direction component of the electric field is actually a tower, and the electrons are ejected from the plasma. This point is drawn on the surface of a magnetic flux tube made up of lines of magnetic force that pass through a circle formed by rotating around the axis of symmetry. Since ?F exists inside, the electrons ejected from the plasma and returning to the plug T will not exit outside the magnetic flux tube (2).

On the other hand, in the present invention, the control electrode αυ passing through the through-hole I and the through-hole a of the -pole al is disposed outside the magnetic flux tube. Therefore, since there is no dielectric breakdown between the control electrode aυ and the cathode a caused by plasma electrons entering the first through hole, a sufficiently high potential barrier is created for each of the electrons and ions, and the plasma confinement time can be extended by *tK. Furthermore, since there is no inflow of plasma electrons into the control voltage fill, a large amount of electrons from the high-temperature, high-density plasma are transferred to the electrostatic plug (lK#). Plasma can also be confined Other embodiments of the invention The present invention relates to an open system plasma device.In the embodiment, a plasma device using a cusp magnetic field will be explained. It goes without saying that the present invention can be applied to, for example, a uniform magnetic field, a t-ray magnetic field, etc. Also, the application of the plasma device is not limited. For example, a fusion reactor, surface processing/treatment, S*, ion It is difficult to apply it to plasma electronic devices such as sources.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of an electromagnetic trap, and FIG. 2 is a diagram showing the distribution of space potential near two axes of the electromagnetic trap. FIG. IIIE3 is a configuration diagram of a plasma device showing one embodiment of the present invention. FIG. 4 is a diagram showing the configuration and function of the main mating section of the embodiment shown in FIG. 3. (→ is a configuration diagram of an electrostatic plug. (b) is a diagram showing the two-dimensional dependence of the space potential φ(r, g), (
C) is a diagram showing the dependence of space potential φ(r, x) on r. (ri...coil, (2), +4), +9)...
Anode, (3), (5) 1... Cathode, (6)... Boundary of space where plasma exists. ■...Control electrode, 0/Koni electrostatic plug, (is,
α4. (c)...power supply, ag...th wall, -...
Plasma, α−...through hole, (to)...anode ω
)... hollow part.

Claims (1)

[Scope of Claims] A device for generating an open magnetic field containing plasma, a means for controlling the electric potential of a space where the plasma exists, and a device disposed at the open end of the open magnetic field and parallel to the direction of the magnetic field. In a plasma device that polarizes an electrostatic plug that forms an electric field with a non-zero component. At least one of the electrostatic plugs has a cathode that intersects with magnetic lines of force passing through the space where the plasma exists and lines of magnetic force circumscribing the space where the plasma exists, and a cathode that is disposed between Kouya Kouya and the plasma so that one of the lines of magnetic force intersects with the line of magnetic force that circumscribes the space where the plasma exists. an anode that encloses the anode without being mixed with the magnetic force, a through hole drilled in a part of the anode that does not intersect with the magnetic force, and a control electrode that passes through the crease through hole without contacting the cathode and extends into the internal space of the anode. A plasma device comprising: a means for applying a lower potential to the anode than the control electrode; and a means for applying a higher potential to the anode than the control electrode.