Three-dimensional non-linear magnetohydrodynamic modeling of massive gas ă injection triggered disruptions in JET
Résumé
JOREK 3D non-linear MHD simulations of a D-2 Massive Gas Injection (MGI) ă triggered disruption in JET are presented and compared in detail to ă experimental data. The MGI creates an overdensity that rapidly expands ă in the direction parallel to the magnetic field. It also causes the ă growth of magnetic islands (m/n = 2/1 and 3/2 mainly) and seeds the 1/1 ă internal kink mode. O-points of all island chains (including 1/1) are ă located in front of the MGI, consistently with experimental ă observations. A burst of MHD activity and a peak in plasma current take ă place at the same time as in the experiment. However, the magnitude of ă these two effects is much smaller than in the experiment. The simulated ă radiation is also much below the experimental level. As a consequence, ă the thermal quench is not fully reproduced. Directions for progress are ă identified. Radiation from impurities is a good candidate. (C) 2015 AIP ă Publishing LLC.