TERP, a non circular toroidal pinch

Turbulent heating in high voltage, low density (<1014cm-3) theta pinches is a proven technique for heating large volumes of plasma to thermonuclear temperatures. The TERP experiment is designed to investigate some of the problems that arise in trying to transfer these concepts from straight theta pinch geometry to a toroidal confinement system. Various considerations have led to a small aspect ratio turbulent heating experiment with A approximately equal to 2 - 3 which in turn has led to consideration of noncircular cross section Tokamak-like confinement systems. The investigations began by studying the relaxation to equilibrium and the excitation of MHD instabilities after the initial implosion. Two cases have been studied, one with a filling pressure of 1 mTorr of argon and the other with 10 mTorr of hydrogen. The implosion phase is much more rapid and diffusive in hydrogen but the late time MHD behavior appears to be similar for both plasmas although the macroscopic velocities are again faster in hydrogen. (U.K.)