US3009080A - Apparatus and method for generating and containing plasma having ultrahigh temperatures - Google Patents

Description

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Nov. 14, 1961 APPARATUS AND METHOD FOR GENERATING AND CONTAINING PLASMA HAVING ULTRA-HIGH TEMPERATURES Filed Oct. 23, 1959 H. G. L008 2 Sheets-Sheet 1 IN VEN TOR. A E/VDQ/CZ/S" 6*. L005 Nov. 14, 1961 H. G. Loos 3,009,030 APPARATUS AND METHOD FOR GENERATING AND CONTAINING PLASMA HAVING ULTRA-HIGH TEMPERATURES Filed Oct. 23, 1959 2 Sheets-Sheet 2 52 59 IN V EN TOR.

S AE/VDQ/C'VE G. 4 BY nited States 3,39,080 Patented Nov. 14, I961 [ice 3,099,080 APPARATUS AND METHQD FOR GENERATING AND CONTAINING PLASMA HAVING ULTRA- HIGH TEMPERATURES Hendricus G. Loos, Costa Mesa, Calif., assignor to Plasmadyne Corporation, Santa Ana, Calif., a corporation of California Filed Oct. 23, 1959, Ser. No. 848,377 14 Claims. (Cl. 315-111) This invention relates to an apparatus and method for generating plasma having ultra-high temperatures, and for eflecting stable containment of such plasma.

An object of the present invention is to effect magneticpunch generation of ultra-high temperature plasma in a curved envelope, and to prevent blowing and instability of the generated plasma.

A further object is to provide an apparatus and method for effecting generation and containment of plasma in an endless conductor means, so that there can be no end elfects.

A further object of the invention is to provide means for compensating for the unequal bunching of the lines of magnetic force which are employed to generate ultrahigh temperature plasma by the rnagnetic-punch method, thereby making it feasible and practical to generate and contain plasma in toroids and other endless elements.

A further object is to provide apparatus for generating ultra-high temperature plasma, for laboratory purposes and possibly for use as an igniter in controlled fusion apparatus, in the absence of electrodes and without cooling or contamination of the plasma by the envelope.

These and other objects and advantages of the invention will be set forth more fully in the following specification and claims, considered in connection with the attached drawings to which they relate.

In the drawings:

FIGURE 1 is a plan view illustrating an apparatus constructed in accordance with the present invention;

FIGURE 2 is a vertical section taken on the broken line 22 of FIGURE 1;

FIGURE 3 is a horizontal section of the apparatus, taken on line 33 of FIGURE 2;

FIGURE 4 is an enlarged transverse sectional view corresponding to the right portion of the showing of FIGURE 2, but schematically representing the currents and magnetic fields; and

FIGURE 5 is an exploded schematic perspective view illustrating the various cur-rent conductors and the means for supplying electrical power thereto.

Throughout this specification and claims, phrases such as axis of the toroid will be employed to denote the axis about which a circle is revolved to generate the toroid. On the other hand, phrases such as axis of the toroidal (or curved) chambers denote the locus of the center of the circle thus revolved.

Referring to the drawings, the apparatus comprises electrically-conductive wall means It} shaped as a hollow toroid having a toroidal chamber 11 therein. The illustrated wall means is of segmented construction and comprises three sections each having upper and lower semitubular curved portions 12 and 13, respectively. Elements 12 and 13 have inner flanges 14 and 15, respectively, disposed relatively close to the axis of the toroid.

' The flanges 14 and 15 of each of the three sections of the toroid are disposed in surface abutment with each other to minimize contact resistance therebetween, being maintained together by means of a series of bolts indicated at 16.

Upper and lower sections 12 and 13 also have outer flanges 17 and 18, respectively, extending away from the axis of the toroid. The flanges 17-and 18 of each section of the toroid are parallel and adjacent each other but are not in electrical contact, being separated by insulation indicated at 19. Bolts 20 are employed to maintain flanges 17 and 18 in the described positions adjacent opposite surfaces of insulation 19, such bolts being insulated from the flanges by insulation means indicated at 21. It is pointed out that all of the flanges 14-15 and 17-18 lie in medial planes perpendicular to the a is of the toroid.

It is to be understood that the three sections of the wall means 10 forming the toroid may be rigidly assembled together in any suitable manner. Furthermore, it is to be understood that more than three sections may be employed, and that the wall means may be continuous and unitary.

Mounted within the toroidal chamber 11 is an electrically non-conductive continuous toroidal envelope 22, formed of quartz or the like. Envelope 22 has a cylindrical wall portion 23 disposed adjacent the axis of the toroidal chamber. The axis of wall portion 23 is coincident with the axis of the toroid. Envelope 22 also has a semi-tubular wall portion 24 integral with cylindrical wall portion 23 and disposed closely adjacent the interior surface of conductor means 10' between wall portion 23 and the axis of the toroid.

It is to be understood that envelope 22 is suitably cleansed of air and other contaminants, and is filled with deuterium or other desired gas at a low pressure, for example on the order of one one-thousandth of an atmosphere. The portion of toroidal chamber 11 within envelope 22 has been given the reference numeral 25 and constitutes the space in which the plasma is contained.

In the illustrated embodiment, the cylindrical wall portion 23 is on the large-radius side of the curved envelope 22 and of the chamber 25. On the other hand, the part of semitubular wall portion 24 adjacent inner flanges 14 and 15 is on the small-radius side of envelope 22 and of the chamber 25.

Annular electrical conductor means 26 is mounted adjacent the axis of the toroidal chamber 11, and adjacent the center of envelope wall portion 23, but outside the plasma chamber 25. The illustrated conductor means 26 is segmented, being divided into three sections corresponding to the three sections of conductor means 10. The ends of each arcuate section of conductor means 26 are electrically and mechanically connected to radially and outwardly-extending conductor rods 27. Such rods are suitably insulated from flanges 17 and 18 and from conductor sections 12 and 13, so that all current entering the rods 27 must flow through the connected arcuate sections of conductor means 26. As shown best in FIGURE 3, the conductor rods 27 of adjacent sections of conductor means 26 are closely adjacent and parallel to each other.

Referring next to FIGURE 5 wherein the electrical circuits are indicated schematically, capacitor means 28 and trigger means 29 are connected in series with each other between the conductor rods 27 for each section of the annular electrical conductor means 26. In addition, capacitor means 31 and trigger means 32 are connected in series with each other between the upper and lower flanges 17 and 18 of each section of conductor means 10. The capacitor means 28 are charged with corresponding polarities by any suitable means, not shown, so that simultaneous circuit-closing operation of triggers 29 effects current flow longitudinally of the axis of the toroidal chamber 11 in the same direction through each section of conductor means 26. The result simulates the cur-rent flow around a continuous circular conductor. Capacitor means 31 are also suitably charged with corresponding polarities, so that simultaneous circuit-closing operation of triggers 32 effects flow of current in single-turn circuits through conductor sections 12 and 13. It is to be understood that capacitor means 28 and 31 comprise suitable banks of capacitors, and that trigger means 29 and 32 may comprise spark gaps or the like.

A capacitor means 36 and inductor 38 are connected in series with each other across each capacitor means 28. Similarly, a capacitor means 37 and inductor 39 are connected in series with each other across each capacitor means 31. The elements 36-38 and 3739 are adapted to create relatively large, but slow acting, magnetic fields. Thus, for example, capacitor 37 and inductor 39 create a field lasting at least several times longer than the field generated as the result of initial discharge of capacitor means 31. The same relationship applies between capacitor 36 (and inductor 38) and In operation of the apparatus, if elements 36-39, inclusive, were omitted, the gas within envelope 22 is preionized by any suitable means such as by use of radiofrequency waves. Furthermore, the capacitor means 28 and 31 are suitably charged with corresponding polarities, as previously stated, the triggers 29 and 32 then being in open-circuit conditions.

The triggers 29 and 32 are then operated simultaneously to effect discharging of the capacitor means 28 and 31 through the connected circuit elements. The discharging of capacitor means 31 through triggers 32 causes discharge currents, designated I in FIGURE 4, to flow through single-turn circuits including upper flanges 17, upper curved portions 12, inner flanges 14 and 15, lower curved portions 13, and lower flanges 18 back to the capacitor means 31. The described current flow I transversely around the axis of toroidal chamber 11 effects generation in such chamber of a strong magnetic field B having continuous annular lines of force which are parallel to the axis of the chamber. Representative ones of such lines are indicated in FIGURE 4 by dots enclosed in circles. Such symbols indicate that the lines of magnetic force are directed out of the drawing, that is to say clockwise as viewed from above (FIGURE 3).

The discharge of the capacitor means 28 effects flow of currents, designated I in FIGURE 4, through the annular conductor means 26. The direction of such flow is counterclockwise as viewed from above (FIGURE 3), being indicated by the x enclosed in a circle. Currents I effect generation of lines of magnetic force which extend transversely around conductor 26. Such magnetic field is designated B in FIGURE 4, and representative lines of magnetic force are indicated therein by endless lines having arrow points thereon.

As will be described below, the indicated currents and magnetic fields result in generation and containment within plasma chamber 25 of an annular mass of hightemperature plasma indicated at 33 in FIGURE 4. The plasma 33 extends for the full length of the toroidal chamber within conductor means 10.

There will now be considered the condition which would occur if there were no annular conductor means 26. The sudden pulsing of currents 1 would then induce currents in the pre-ionized gas in envelope chamber 25. Such currents would flow, in a current sheet, closely adjacent the interior wall of the envelope 22, and would momentarily prevent the magnetic field B (generated by currents I from extending through the central portions of the chamber 25. Immediately thereafter, magnetic field B would act as a piston to drive or implode the current sheet (ions) within chamber 25 radially inwardly or toward the annular axis of chamber 25. The implosion of ions and electrons is very sudden and powerin], and results in formation of plasma having high temperatures. However, the plasma thus generated would not tend to remain at the axis of chamber 25, or even at the axis of the toroidal chamber 11,. but would in.-

stead tend to be blown outwardly toward the outer flanges 17 and 18. It would thus contact envelope wall portion 23 and be cooled and contaminated thereby. Even if the envelope means 22 had a circular section and extended closely adjacent the entire interior wall of conductor means \10, the plasma would move outwardly into contact with the envelope at points adjacent flanges 17 and 18. Such contact of the plasma with the wall would be fatal since it would result in loss of energy, contamination, and other extreme defects or deficiencies.

The described outward blowing of plasma would result from the fact that the lines of magnetic force in field B (generated by current I are more closely arranged at the shorter radius (adjacent inner flanges 14 and 15) than at the outer radius (adjacent flanges 17 and 18). Thus, since the ions tend to move toward regions where the magnetic field is weakest, the radialoutward blowing would result.

The above-indicated radial-outward blowing of plasma is prevented by the magnetic field B generated by current 1 flowing through annular conductor means 26. As shown in FIGURE 4, field B is largely bunched between conductor means I and the axis of toroidal gas chamber 25. The lines of force in field B therefore prevent the indicated plasma 33 from blowing toward flanges 17 and 18. It follows that the cylindrical wall portion 23 is not engaged by the plasma, and that the plasma is effectively contained and is not cooled and contaminated by envelope material. The magnetic field B not only aids in containing the plasma but also in generating the same, since the fields B and B move generally toward the axis of gas chamber 25 to drive or implode the ionized gas toward such axis and result in the high-temperature plasma indicated at 33.

It is to be understood that FIGURE 4 indicates the magnetic fields as they exist a short time interval after currents have commenced to flow, that is to say after the implosion has been substantially completed so that the plasma 33 has been generated. Thus, the lines of magnetic force have moved away from the interior wall of the envelope means 22 to drive the ionized particles toward the axis of chamber 25. It is also to be understood that the operation occurs in an extremely short period of time, for example on the order of a microsecond. The current flows are very high, on the order of 10 or 10- amperes, so that the magnetic fields are extremely strong.

Description of the method, where elements 36-39 are employed The method, as described above, related only to the first implosion, resulting from initial discharge of capacitor means 28 and 3 1. After such initial discharge, there is an instant when the magnetic fields B and B are zero. Electrical oscillations (ringing) in the described circuits then result in subsequent charging and discharging of the capacitor means 28 and 31. Repeated implosions, or magnetic compression or punching, thus occur to raise the plasmartemperature to even higher levels.

The relatively slow-acting, but long-duration, magnetic fields generated by elements 3649 perform the function of preventing the plasma 33 from expanding into contact with envelope 22 during intervals between the aboveindicated repeated implosions. As an example, the initial discharge of each capacitor 36 or 37 may require the same length of time required by capacitors 28 and 31 to discharge five times.

-It is to be understood that all of the capacitors 28 and 31 may be combined in a single bank, as may the capacitors 36 and 37. This assures that the currents flowing in elements 10 and 26 are in phase, as is desired.

Various embodiments of the present invention, in addition to what has been illustrated and described in detail, may be employed without departing from the scope of the accompanying claims.

I claim:

1. An apparatus for generating and containing ultrahigh temperature plasma, comprising elongated curved envelope means for defining a chamber adapted to contain gas at a small fraction of atmospheric pressure, means to effect flow of current transversely around said envelope means exteriorly of said chamber, said last-named means being adapted to create an implosion in said chamber whereby high-temperature plasma is generated therein, and means to effect flow of current longitudinally of said chamber and exteriorly thereof adjacent the side of said chamber having a relatively large radius in comparison to the diametrically-opposite side of said chamber, said lastnamed means serving to prevent movement of said plasma toward said large-radius side of said chamber.

2. Apparatus for generating and containing plasma having an ultra-high temperature, comprising means to effect sudden fiow of a very high current transversely around an elongated curved space to thereby create an implosion of ionized particles in said space, elongated electrical conductor means disposed longitudinally of said space adjacent the large-radius side thereof, means to effect flow of a very high current in said conductor means simultaneously with said current flow transversely around said space, and means to at least partially evacuate said space prior to said current flows.

3. Apparatus for generating and containing plasma having an ultra-high temperature, which comprises elongated hollow electrical conductor means which curves along its length, said conductor means having a large-radius side and a short-radius side, said conductor means having an insulating split formed longitudinally therein whereby to form single-turn electric circuit means through said conductor means transversely around the chamber therein, means to maintain in said chamber pure gas having a pressure which is a small fraction of atmospheric pressure, an electrical conductor disposed longitudinally of said chamber adjacent said large-radius side of said conductor means, and means to effect instantaneous and simutaneous flows of current through said single-turn circuit means around said chamber and through said electrical conductor longitudinally of said chamber to thereby generate and contain in said chamber ultra-high temperature plasma.

4. The invention as claimed in claim 3, in which said means to maintain said gas in said chamber includes an envelope disposed in said chamber adjacent said shortradius side of said conductor means and spaced from said large-radius side thereof, and in which said elongated conductor is disposed in said chamber exteriorly adjacent said envelope and between said envelope and said large-radius side of said conductor means.

5. Apparatus for generating and containing plasma having an ultra-high temperature, comprising electrical conductor means shaped as a hollow toroid having a toroidal chamber therein, said conductor means having a split therein longitudinally of the axis of said toroidal chamber whereby to form a single-turn circuit through said conductor means transversely around said chamber, envelope means provided in said toroidal chamber to contain gas having a pressure which is a small fraction of atmospheric, elongated conductor means disposed in said chamber adjacent said envelope means and between said envelope means and the larger-radius portion of said toroidal conductor means, and means to create substantially-simultaneous flows of very large currents through said single-turn circuit and through said elongated conductor means to thereby generate and contain ultra-high temperature plasma in said envelope means.

6. Apparatus for generating and containing plasma having an ultra-high temperature, comprising electrical conductor means shaped as a hollow toroid, continuous toroidal envelope means disposed in the chamber within said toroidal conductor means, said envelope means being adjacent the smaller-radius side of said conductor means and spaced from the larger-radius side thereof, said envelope means being adapted to contain a pure gas having a pressure only a small fraction of atmospheric pressure, an annular conductor disposed in the chamber within said toroidal conductor means exteriorly adjacent said envelope means and between said envelope means and said larger-radius side of toroidal conductor means, means to form a single-turn electrical circuit through said toroidal conductor means transversely around said envelope means, and means to effect substantially simultaneous flows of large currents through said single-turn circuit and through said annular conductor to thereby effect an implosion in said envelope means and consequent generation and containment of ultra-high temperature plasma therein.

7. The invention as claimed in claim 6, in which said means to form said single-turn circuit includes a longitudinal split formed through said toroidal conductor means along the larger-radius side thereof.

8. The invention as claimed in claim 6, in which said toroidal conductor means and said annular conductor are segmented, in which terminals are provided for each segment, and in which said current-flow means includes means to supply currents substantially simultaneously to all of said terminals for flow of current simultaneously through the various segments and in the same direction through all corresponding segments.

9. The invention as claimed in claim 6, in which said current-flow means includes a plurality of capacitors, and means to effect substantially simultaneous discharge of said capacitors through said single-turn circuit and through said annular conductor.

10. The invention as claimed in claim 6, in which said envelope means has a wall portion which conforms closely to the inner wall of said toroidal conductor means along the small-radius side thereof, and has a cylindrical wall portion disposed adjacent the axis of the toroidal chamber within said toroidal conductor means.

11. Apparatus for generating and containing plasma having an ultra-high temperature, comprising endless curved envelope means to contain a pure ga having a pressure only a small fraction of atmospheric, means to effect sudden current flow transversely around substantially all portions of said envelope means to thereby effect magnetic-punch generation of an endless region of plasma therein, and means to create a magnetic field counteracting the tendency of said generated plasma to be blown toward the larger-radius side of each section of said envelope means, said last-named means including elongated conductor means extending longitudinally of said envelope means along the larger-radius side thereof.

12. Apparatus for generating and containing plasma having an ultra-high temperature, comprising endless curved envelope means to contain a pure gas having a pressure only a small fraction of atmospheric, means to effect suddent current flow transversely around substantially all portions of said envelope means to thereby effect magnetic-punch generation of an endless region of plasma therein, means to create a magnetic field counteracting the tendency of said generated plasma to be blown toward the larger-radius sideof each section of said envelope means, said cunrent-flow means being adapted to effect current flow in an oscillatory or ringing manner through a number of oscillations, and auxiliary means to effect containment of said plasma during intervals between oscillations.

13. Apparatus for generating and containing plasma having an ultra-high temperature, comprising endless curved envelope means to contain a pure gas having a pressure only a small fraction of atmospheric, means to effect sudden current flow transversely around substantially all portions of said envelope means to thereby effect magnetic-punch generation of an endless region of plasma therein, means to create a magnetic field counteracting the tendency of said generated plasma to be blown toward the larger-radius side of each section of said envelope means, said current-flow means being adapted to effect current flow in an oscillatory or ringing manner through a number of oscillations, and auxiliary means to elfect containment of said plasma during intervals between oscillations, said auxiliary means comprising means to create a magnetic field around said chamber and continuing for a number of oscillations of current in said current-flow means.

14. Apparatus for generating and containing plasma having an ultra-high temperature, which comprises Wall means to define a chamber having gas therein at only a small fraction of atmospheric pressure, electromagnetic means to create a plurality of sequential magnetic implosions in said chamber in very rapid sequence and sufficiently strong to generate ultra-high temperature References Cited in the file of this patent UNITED STATES PATENTS Josephson Jan. 13, 1959 Spitzer Oct. 27, 1959

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