Imploding Liner Compression of a Field-Reversed Configuration With Diffusional Losses

Abstract

Compression of a magnetized plasma in the form of a field-reversed configuration (FRC) to megagauss magnetic field levels by implosion of a surrounding cylindrical liner of liquid metal must address the need for implosion times sufficiently short compared with various loss times from the FRC. This issue is examined in the context of FRCs with high elongation, which may allow stability. Implosion times comparable to the initial value of loss time for magnetic flux, scaling energy, and particle loss times appear adequate to achieve large gains in plasma energy and temperature during compression. With loss based on neoclassical transport, liners at feasible drive pressures and initial diameters of tens of centimeters should be satisfactory for useful compressions of FRCs. In the dimensionless analyses presented, the product of liner speed and initial plasma radius indicates the importance of high initial temperature (~500–800 eV) to reduce the size and cost at allowable drive pressures for the stabilized liner implosion.