Momentum-space analysis of suprathermal electrons generation under conditions of gas puffing during runaway tokamak discharges

摘要

1. Introduction The energy of disruption generated runaway electrons can reach as high as tens of megaelectron-volt energy and they can cause a serious damage of plasma-facing-component surfaces in large tokamaks like ITER [1]. The precise measurement of runaway electron parameters during disruptions is not so easy to carry out. At the same time, the quiescent runaway electron generation during the flat-top of DIII-D low density Ohmic discharges allows accurate measurement of all key important parameters to runaway electron excitation [2, 3]. Precise measurements of RE distribution functions and dissipation rates in the spatial, temporal and energy domains were carried out, a new effective diagnostic called the "Gamma Ray Imager" was applied. Quantitative discrepancies between experimental measurements and modeling were found for all RE energies, but the most qualitative discrepancy was found at low energy.