Systems and methods for radial and axial stability control of an frc plasma

Abstract

Systems and methods are provided that facilitate stability of an FRC plasma in both radial and axial directions and axial position control of an FRC plasma along the symmetry axis of an FRC plasma chamber. The systems and methods exploit an axially unstable equilibria of the FRC plasma to enforce radial stability, while stabilizing or controlling the axial instability. The systems and methods provide feedback control of the FRC plasma axial position independent of the stability properties of the plasma equilibrium by acting on the voltages applied to a set of external coils concentric with the plasma and using a non-linear control technique.

What is claimed is: 
     
         1 . A system for stabilizing a field reversed configuration (FRC) plasma within a confinement chamber comprising
 a confinement chamber,   first and second divertors coupled to first and second ends of the confinement chamber,   first and second axial plasma guns operably coupled to the first and second divertors, the first and second formation sections and the confinement chamber,   a plurality of neutral atom beam injectors coupled to the confinement chamber and oriented to inject neutral atom beams toward a mid-plane of the confinement chamber at an angle less than normal to a longitudinal axis of the confinement chamber,   a magnetic system comprising a plurality of quasi-dc coils positioned around the confinement chamber, the first and second formation sections, and the first and second divertors, first and second set of quasi-dc mirror coils positioned between the confinement chamber and the first and second formation sections, and first and second mirror plugs position between the first and second formation sections and the first and second divertors,   a gettering system coupled to the confinement chamber and the first and second divertors,   first and second set of radial magnetic field coils configured to generate first and second radial magnetic fields within chamber, and   a control system operably coupled to the quasi-dc coils and the first and second radial magnetic field coils, the control system including a processor coupled to a non-transitory memory comprising a plurality of instruction that when executed causes the processor to tune the magnetic field generated by the plurality of quasi-dc coils and the first and second radial field coils to stabilize an FRC plasma in a radial direction normal to a longitudinal axis of the chamber to position the FRC plasma axisymmetric about the longitudinal axis and in an axial direction along the longitudinal axis of the confinement chamber.   
     
     
         2 . The system of  claim 1  wherein the control system is configured to tune the magnetic field generated by the plurality of quasi-dc coils to induce stability in the FRC plasma in a radial direction normal to a longitudinal axis of the confinement chamber wherein the FRC plasma is positioned axisymmetric about the longitudinal axis of the confinement chamber, and to induce instability in the FRC plasma in an axial direction along the longitudinal axis of the confinement chamber. 
     
     
         3 . The system of  claim 2  wherein the control system is configured to tune the first and second radial magnetic fields generated by the first and second radial coils to interact with the FRC magnetic field positioned about the FRC plasma to induce stability in the FRC plasma in the axial direction along the longitudinal axis of the confinement chamber. 
     
     
         4 . The system of  claim 1  wherein the system is configured to generate an FRC plasma and maintain the FRC plasma at or about a constant value without decay while neutral atom beams are injected into the FRC plasma. 
     
     
         5 . The system of  claim 3  wherein the first and second radial magnetic fields are antisymmetric about the mid-plane. 
     
     
         6 . The system of  claim 1  further comprising first and second diametrically opposed FRC formation sections coupled to the first and second divertors, the formation section comprising modularized formation systems for generating a formation FRC plasma and translating the formation FRC plasma toward a midplane of the confinement chamber. 
     
     
         7 . The system of  claim 7  further comprising third and fourth divertors coupled to the first and second diametrically opposed FRC formation. 
     
     
         8 . The system of  claim 1  wherein the control system is configured to control the radial electric field profile in an edge layer of the FRC plasma by applying a distribution of electric potential to a group of open flux surfaces of the FRC plasma with biasing electrodes. 
     
     
         9 . The system of  claim 1  wherein the gettering system includes one of a Titanium deposition system and a Lithium deposition system. 
     
     
         10 . The system of  claim 1  wherein the control system is configured to form a formation FRC plasma in the first and second formation sections and accelerate the formation FRC plasma towards the mid-plane of the chamber to form the FRC plasma. 
     
     
         11 . The system of  claim 1  further comprising quasi-dc mirror coils extending about the opposing ends of the confinement chamber generating a mirror magnetic field within opposing ends of the confinement chamber. 
     
     
         12 . The system of  claim 1  wherein the control system is configured to monitor the position of the FRC plasma. 
     
     
         13 . The system of  claim 12  wherein the control system is configured to monitor the magnetic measurements associated with the FRC plasma. 
     
     
         14 . The system of  claim 12  wherein the control system is configured to measure the current in the first and second radial coils. 
     
     
         15 . The system of  claim 12  wherein the control system is configured to monitor the velocity of the FRC plasma.