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Section: New Results

Full MHD Modeling of Shattered Pellet Injection

Participants : B. Nkonga, P. Chandrashekar, A. Bhole.

To avoid disruptions, the first thing to do is to operate as far as possible from disruptions operational limits. It means that plasma scenarios must be designed taking these limits into account. The challenge is to deal with peeling-ballooning instabilities called Edge Localized Modes (ELMs) which are characterized by the quasi-periodic relaxation of the pressure pedestal profile which results in the expelling of particles and energy from the bulk plasma to the edge. Injecting of impurities is one of the solutions to change the pedestal profile and mitigate MHD instabilities. The current design of the ITER DMS(Disruption Mitigation System) is a hybrid system using Massive Gas Injection (MGI) and Shattered Pellet Injection (SPI), methods which have demonstrated their efficiency on current tokamaks (JET, DIIID, …). Considering that the plasma is composed of impurities, main ion core and set of electrons, premixed “Full MHD” formulation has been proposed. This model assumes that, for any control volume, the plasma is locally neutral and at the thermal and coronal equilibrium. Properties of this model are under analysis, according to the tabulated equation of state. A numerical approximation in the Jorek Code is also under progress. This work has been done in the context of the JET program 2019.