Ultra-Low-q Discharges in REPUTE-1

Abstract

The characteristics of ultra-low-q discharges (0<q_a<1) have been studied in REPUTE-1. Results from magnetic probe measurements and parameter scans for the discharges are described. It is found that a q profile with d_q/d_r<0 is formed in the setting-up phase and a high density plasma with the order of ñ_e-10²⁰m^-3 is obtained during the discharge duration of about 15 msec for low toroidal fields (<2 kG).