ESTIMATION OF CURRENT PROFILE DURING ION-CYCLOTRON RANGE OF FREQUENCYHEATED DISCHARGES CHARACTERIZED BY SAWTOOTH STABILIZATION AND CRASH IN JT-60U

Sawteeth are stabilized by the second harmonic Ion Cyclotron Range of Frequency minority ion heating in JT-60U. In these discharges, time ev olution of the current profile is studied by using a 1.5D transport co de in order to understand the effect of sawtooth crash on the current profile and to determine whether the plasma conductivity is given by S pitzer or by neoclassical formulae. The computational results using re set q profile at experimental sawtooth crash time and the neoclassical conductivity are in good agreement with experimental observations. Th e resistive diffusion of the current is neoclassical except at the cra sh and the current profile abruptly changes at the crash.