ION HEAT PULSE AFTER A SAWTOOTH CRASH IN THE JAERI FUSION TORUS-2M TOKAMAK

The ion heat pulse after a sawtooth crash is studied by a time-of-flig ht (TOF) neutral measurement. A rapid change of the bulk ion energy di stribution near the edge is observed after a sawtooth crash. The delay time is measured, and the effective measuring position is estimated b y a neutral transport code. Then a transient ion thermal conductivity, chi(i)(HP), of about (7-18) m(2)/s is evaluated for the low confineme nt mode (L-mode) plasma. The simple diffusive model with constant chi( i)(HP), however, does not explain the amplitude of the pulse in the io n energy distribution. (C) 1996 American Institute of Physics.