Cross-field resistivity scaling with density and temperature for steady-state FRCs under rotating magnetic field current drive

FRCs can be sustained in steady state by Rotating Magnetic Fields at densities relevant to fusion reactors. The obtainable density scales linearly with the RMF magnitude Bω and inversely with the plasma resistivity. The RMF power required to sustain the FRC current and flux is also directly proportional to the total toroidal current and the average resistivity. It has been found in TCS experiments that as the plasma temperature is increased by using anti-symmetric RMF drive, or by reducing the impurity level, that despite higher currents and magnetic fields, the RMF power required to maintain the configuration does not increase significantly. This is due to most of the added diamagnetic current being carried in a low resistivity core near the FRC field null, and also to a resistivity that appears to scale as 1/B. Past experiments have been limited in temperature by high impurity levels and low Z radiation barriers, and experiments at higher temperatures will be reported in a new device, TCS/upgrade, significantly upgraded to produce clean plasmas. (author)