COMPARATIVE STUDIES OF A SPHERICAL TOKAMAK AND A CONVENTIONAL TOKAMAK: MAGNETIC TURBULENCE-INDUCED TRANSPORT

摘要

The paper reports experiments on turbulence-induced transport in plasmas with aspect ratios A ofrn1.4 ～ 2.5 in a single machine. There is little aspect ratio dependence in electrostatic fluctuations. Thernrelative levels of magnetic fluctuations in the core region are 0.01% and 0.05% for A = 1.4 and 2.5,rnrespectively. The electron heat transport estimated from the magnetic fluctuation level of 0.01% is 0.2rnkW/m~2, which is less than 2% of the electron heat flux of 13 kW/m~2 estimated from the global powerrnbalance. Thus in spherical tokamaks, the present results show that magnetic fluctuations are not responsiblernfor electron heat transport, as in conventional tokamaks.