Magnetic pumping in spatially inhomogeneous magnetic fields

Claim 2

Apparatus for heating a toroidally extending plasma column in an ATC having poloidal and toroidal coil means and toroidal containment means, comprising: a. means for producing a magnetic field having spaced apart regions of stability and an unstable region therebetween for providing unbalanced biasing forces on the plasma column along the radial axes of the containment means for alternately, periodically and oppositely displacing the plasma column radially back and forth between the regions of stability in the plane of the containment means within a time period ti of an average ion-ion collision time; and b. means for modulating said poloidal coil means.

Claim 3

In the method of heating a toroidally extending current carrying plasma column in the ATC in a system of first and second current carrying poloidal and first toroidal coil means distributed so as to produce vertical curved magnetic field lines and magnetic field shapes having equilibrium regions of stability within a closed toroidal containment means for establishing the plasma column in first and second positions spaced from the inside wall of the containment means, the plasma column being stabilized along a transverse axis parallel to the axis of rotation of the containment means, radial axes extending from said axis of rotation in the plane of the toroidal containment means, and an endless equilibrium axis extending in the plasma column coaxially with the plasma current, the improvement, comprising the steps of: a. flowing current through the poloidal coil means and distributing the same to produce a magnetic field shape forming spaced apart stability regions having an instability region in the middle region between the spaced apart regions of stability so that said magnetic field shape in said middle region is adapted to provide an unbalanced magnetic biasing force on the plasma column along said radial axes for displacing the plasma column radially from one of said regions of stability to the other in an average ion-ion collision time or less; and b. pushing the plasma column back and forth by modulating said current flowing through said poloidal coil means alternately periodically to change the direction of the biasing force in the regions of stability in the spaces in the closed containment means on either side of the instability region so that the plasma column is initially displaced radially into the middle region along said radial axes in the direction of said axis of rotation so as to cause said plasma column to be displaced radially inwardly to said second position and compressed thereby within an average ion-ion collision time period ti or less to increase the temperature of said plasma column, and for returning the plasma column to the aforesaid first position in a cycle successively to compress and expand the plasma column in a cycle that irreversibly heats the plasma column in accordance with the number of the cycles that are produced within the plasma relaxation time period tE from the initial temperature and density of the plasma current carrying plasma column defined by the total energy of the plasma column divided by the power for maintaining that total energy by the flowing of the currents through the toroidal and poloidal coil means.

Claim 4

In the method of heating a toroidally extending current carrying plasma column in the ATC in a system of first and second current carrying poloidal and first toroidal coil means distributed so as to produce vertical curved magnetic field lines and magnetic field shapes having equilibrium regions of stability within a closed toroidal containment means for establishing the plasma column in first and second positions spaced from the inside wall of the containment means, the plasma column being stabilized along a transverse axis parallel to the axis of rotation of the containment means, radial axes extending from said axis of rotation in the plane of the toroidal containment means, and an endless equilibrium axis extending in the plasma column coaxially with the plasma current, the improvement, comprising the steps of: a. flowing current through the poloidal coil means and distributing the same to produce a magnetic field shape forming spaced apart stability regions having an instability region in the middle region between the spaced apart regions of stability so that said magnetic field shape in said middle region is adapted to provide an unbalanced magnetic biasing force on the plasma column along said radial axes for displacing the plasma column radially from one of said regions of stability to the other in an average ion-ion collision time or less; and b. pushing the plasma column back and forth by modulating said current flowing through said poloidal coil means alternately periodically to change the direction of the biasing force in the regions of stability in the spaces in the closed containment means on either side of the instability region so that the plasma column is initially displaced radially into the middle region along said radial axes in the direction of said axis of rotation so as to cause said plasma column to be displaced radially inwardly to said second position and compressed thereby within an average ion-ion collision time period ti or less to increase the temperature of said plasma column, and for returning the plasma column to the aforesaid first position in a cycle successively to compress and expand the plasma column in a cycle that irreversibly heats the plasma column in accordance with the number of the cycles that are produced within the plasma relaxation time period tE from the initial temperature and density of the plasma current carrying plasma column defined by the total energy of the plasma column divided by the power for maintaining that total energy by the flowing of the currents through the toroidal and poloidal coil means.

Claim 5

The method of claim 2 in which said modulation is applied to the current carryIng poloidal coil means for producing a modulation in the plasma current to produce said biasing force.

Claim 6

The method of claim 2 in which the modulation is within a relaxation time tE of up to about 3000 microseconds in said ATC, and said average ion-ion collision time is up to about 100 microseconds in 10 2 grams of DT plasma having a density of at least 1013 ions/cm3 at a temperature of at least 200 eV.

Claim 7

The method of claim 2 wherein the initial field shape provides in the plane of the toroidal containment means first and second regions of stability, and sandwiched therebetween a middle-region of marginal instability toward radial plasma column displacement; and wherein said magnetic field shape is changed in the middle region to be fully unstable toward the radial displacement of the plasma column in an average ion-ion collision time ti or less; and wherein said flowing current is periodically alternately increased and decreased to push the plasma column into the fully unstable middle-region so as alternately to produce said compression and expansion respectively within an average ion-ion collision time ti or less for producing the irreversible heating of the plasma column without fast high voltage switching means for increasing the currents in the toroidal coil means or for increasing the aspect ratio of said containment means to produce said first biasing force.

Claim 8

The method of claim 5 wherein current is flowed through the poloidal coil means to produce in the middle region a magnetic field gradient and field lines that curve convexly toward the axis of rotation of the containment means, said convex curving of the field lines in said middle region increasing in opposite directions in the plane of the containment means from a zero curve respectively in said regions of stability.

Claim 9

The method of claim 6 in which the current flow in the poloidal coil means is modulated up to only 5% to produce said biasing force at a frequency of up to only every 3000 microseconds for one complete cycle in 10 2 grams of plasma at a density of at least 1013 ions/cm3.

Claim 10

The method of claim 7 wherein said current flowing step, comprises: flowing said current in series in said first poloidal field coil means, adjacent coils having different numbers of windings so as to produce the magnetic field shapes for a period of time to cause the unbalanced magnetic biasing force on the plasma column along the radial axes in the direction of the axis of rotation to cause the plasma column to be displaced radially inwardly from the first to the second position and compressed thereby irreversibly to increase the temperature of the plasma column within an average ion-ion collision time or less.

Claim 11

The method of claim 8 in which the modulating step, comprises: alternately periodically increasing and decreasing the aforesaid current so as to alter the aforesaid magnetic field shapes for a period of time cyclically to bias the plasma column between the aforesaid first and second positions successively to compress and expand the plasma column in a cycle that irreversibly heats the plasma column in accordance with the intensity of said plasma current and the relaxation time period tE of the plasma column as determined by the initial temperature and density of the plasma column, the total energy of the plasma column, and the power for maintaining that total energy.