Hot-tail electrons’ impact on assimilation and injection penetration of D2 Shattered Pellet Injections

The fragment ablation rate plays significant roles in the mitigation efficiency of Shattered Pellet Injection (SPI) as a Disruption Mitigation System (DMS). Current mainstream 3D MHD codes modelling SPIs mostly assume instantaneous thermalization between previously hot ambient electrons and newly released cold electrons, which results underestimation if electron time is comparable or even longer than flying time. To resolve this doubt, we hereby investigate dynamics overall hot-electron impact. finite-time collisional hot-tail rapidly cooling plasma, well so-called ``self-limiting'' effect are considered. former tends to deplete colder population within species, while latter found preferentially higher energy population. combined result cause an almost self-similar decay distribution function, its shape does not deviate much from that Maxwellian mean change during process. Based on observation, axisymmetric JOREK D2 SPI simulations were carried out with additional contribution evaluate their impact onto injection assimilation penetration. It indeed causes enhanced shallower penetration, although depends exact configuration, slow showing negligible fast single non-shattered pellet case shows drastic enhancement. For ITER-like parameters, there no deviation total assimilation, but some penetration observed for velocity cases.