Edge safety factor at the onset of plasma disruption during VDEs in JT-60U

Sugihara, Masayoshi; Lukash, V.*; Khayrutdinov, R.*; Neyatani, Yuzuru

Detailed examinations of the value of the edge safety factor q at the onset of thermal quench during intentional VDE experiments in JT-60U are performed using two different reconstruction methods, FBI/FBEQU and DINA. Results by both methods are very similar and show that the thermal quench occurs when the q value is in the range between 1.5-2. This result suggests that the predictive simulations for VDEs should be performed within this range of q to examine the subsequent differences in the halo currents, plasma movement and other plasma behavior during the current quench.