Method and apparatus for producing average magnetic well in a reversed field pinch
First Claim
1. A method for generating and containing plasma in a reversed field pinch with a magnetic well, said method comprising:
- generating toroidal plasma in a toroidal chamber having a major toroidal axis and a minor toroidal axis and a small aspect ratio;
passing current through said plasma in the direction in which said minor toroidal axis extends to form a strongly reversed magnetic field pinch configuration therein which generates a set of nested closed magnetic flux surfaces defining an elliptic magnetic axis within said plasma extending in the direction of current flow and produces a safety factor q which changes sign within said plasma at the flux surface where the component of the magnetic field in the direction in which said minor toroidal axis extends changes sign; and
generating at least one hyperbolic magnetic axis outside substantially all of said plasma and between said elliptic magnetic axis and said major toroidal axis to form an average magnetic well encompassing substantially all of said plasma.
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Abstract
A magnetic well reversed field plasma pinch method and apparatus produces hot magnetically confined pinch plasma in a toroidal chamber having a major toroidal axis and a minor toroidal axis and a small aspect ratio. A reversed magnetic field pinch current channel within the plasma and at least one hyperbolic magnetic axis outside substantially all of the plasma form thereby a region of average magnetic well in a region of nested closed magnetic surfaces surrounding the plasma current channel when the magnetic field component in the direction of the hyperbolic magnetic axis is also made to be substantially less than zero in the vicinity of the hyperbolic magnetic axis. The magnetic well reversed field pinch is operated so that reversal of the safety factor q and of the toroidal magnetic field takes place within the plasma, and the plasma so produced closely approximates known theoretical stability conditions. The well-producing plasma cross section shape is produced effectively by an exterior shaping shell assembly. The plasma is formed inside a vacuum chamber and an electrically conducting shaping shell assembly, whose noncircular poloidal cross section imparts the desired shape to the plasma. The shape of the plasma may be maintained and/or adjusted by means of electrical currents driven through appropriately distributed external conductors.
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Citations
32 Claims
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1. A method for generating and containing plasma in a reversed field pinch with a magnetic well, said method comprising:
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generating toroidal plasma in a toroidal chamber having a major toroidal axis and a minor toroidal axis and a small aspect ratio; passing current through said plasma in the direction in which said minor toroidal axis extends to form a strongly reversed magnetic field pinch configuration therein which generates a set of nested closed magnetic flux surfaces defining an elliptic magnetic axis within said plasma extending in the direction of current flow and produces a safety factor q which changes sign within said plasma at the flux surface where the component of the magnetic field in the direction in which said minor toroidal axis extends changes sign; and generating at least one hyperbolic magnetic axis outside substantially all of said plasma and between said elliptic magnetic axis and said major toroidal axis to form an average magnetic well encompassing substantially all of said plasma. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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- 16. The method according to any one of clams 1 to 6 wherein said well is formed substantially at a said magnetic flux surface within said plasma where the absolute value of the safety factor q is greater than its absolute value anywhere within said magnetic flux surface on which magnetic field reversal occurs.
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18. Apparatus for generating and containing plasma with a magnetic well reversed field pinch, said apparatus comprising:
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means defining a toroidal chamber having a major toroidal axis and a minor toroidal axis and a small aspect ratio; means for generating a plasma within said chamber; means for passing current through said plasma in the direction in which said minor toroidal axis extends to form a strongly reversed magnetic field pinch configuration therein which generates a set of nested closed magnetic flux surfaces defining an elliptic magnetic axis within said plasma extending in the direction of current flow and produces a safety factor q which changes in sign within said plasma at a said magnetic flux surface where the component of the magnetic field in the direction in which said minor axis extends changes sign; and means for generating at least one hyperbolic magnetic axis outside substantially all of said plasma and between said elliptic magnetic axis and said major toroidal axis to form an average magnetic well encompassing substantially all of said plasma. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A magnetic well reversed field punch plasma device comprising wall means forming a toroidal chamber having a major toroidal axis and a minor toroidal axis and a small aspect ratio;
- and means for generating plasma within said chamber and maintaining a safety factor q which changes sign within said plasma and for producing an average magnetic well encompassing substantially all of said plasma, including means for passing current through said plasma in a pinch current channel disposed within said plasma and extending in the direction in which said minor toroidal axis extends, said channel containing a set of nested closed magnetic surfaces defining an elliptic magnetic axis in the direction of current flow, and means for generating at least one hyperbolic magnetic axis outside substantially all of said plasma and between said channel and said major toroidal axis.
Specification