Comparison of JET AVDE disruption data with M3D simulations and implications for ITER

Nonlinear 3D MHD asymmetric vertical displacement disruption simulations have been performed using JET equilibrium reconstruction initial data. Several experimentally measured quantities are compared with the simulation. These include vertical displacement, halo current, toroidal current asymmetry, and toroidal rotation. The experimental data and the simulations are in reasonable agreement. Also compared was the correlation of the toroidal current asymmetry and the vertical displacement asymmetry. The Noll relation between asymmetric wall force and vertical current moment is verified in the simulations. Also verified is the toroidal flux asymmetry. Although in many ways, JET is a good predictor of ITER disruption behavior, JET and ITER can be in different parameter regimes, and extrapolating from JET data can overestimate the ITER wall force

Theory and modelling activities in support of the ITER disruption mitigation system

International audienceIn 2018, an international Task Force (TF) dedicated to the ITER Disruption Mitigation System (DMS) has been formed. The present paper summarizes Theory and Modelling (T&M) activities performed within this TF. The ITER DMS is planned to rely on Shattered Pellet Injection (SPI). The most critical issue, at present, is that of Runaway Electrons (REs). Indeed, recent T&M work suggests that previously envisaged means of RE avoidance or mitigation may prove inefficient. However, RE simulations have not yet taken into account the possibly beneficial role of magnetohydrodynamic (MHD) instabilities. Furthermore, new promising schemes for RE avoidance or mitigation are being investigated. These comprise, among others: 1) a prompt plasma dilution before the disruption by means of pure H2 SPI in order to suppress hot tail RE generation, and 2) should a RE beam form, a "cleanout" of the beam's companion plasma, via (again) pure H2 SPI into the beam, which may lead to a benign beam termination. The paper also discusses the status of 3D MHD modelling. The JOREK, M3D-C 1 and NIMROD codes have been extended in recent years to be able to simulate SPI. Good cooperation exists betwee