OBSERVATION OF MAGNETOHYDRODYNAMIC STABILITY LIMIT IN A CUSP-ANCHOREDGAS-DYNAMIC TRAP

In this paper, the observation of magnetohydrodynamic (MHD) stability limit in a fully axisymmetric gas-dynamic trap is reported. Transition through the stability boundary was studied by varying the plasma pres sure in the stabilizing cusp end cell and simultaneously measuring the particle and energy lifetimes in the central cell. Energy and particl e balance of the neutral beam heated plasma was measured and compared in unstable and stable regimes of operation. It was observed that if t he calculations based on the energy principle predicted the plasma to be stable experimentally measured transverse losses appeared to be sma ller than the longitudinal ones. In the opposite case, the transverse losses were dominant thus indicating transition through the MHD stabil ity boundary in the cusp-anchored gas-dynamic trap. (C) 1997 American Institute of Physics.