TRANSPORT ET PERTES DE PARTICULES ALPHA PRODUITES PAR LES REACTIONS DE FUSION EN PRÉSENCE D'INSTABILITÉS MHD Une approche de particules passives utilisant le nouveau simulateur toroïdal accéléré de particules en full-orbit (TAPAS)

Abstract

International audienceThe confinement of highly energetic alpha particles is of uttermost importance, for they must transfer their energy to the thermal plasma in order to ensure the self-sustainment of fusion reactions. The present paper focuses on this issue by combining gyro-fluid modelling of a recent JET discharge using the FAR3d code and the integration of trajectories of passive fusion-born alpha particles using the recently developed full-orbit Toroidal Accelerated PArticle Simulator (TAPAS). Special emphasis is put on the impact of magnetohydrodynamic activity triggered by energetic particles on the confinement of alpha particles. In the analysed discharge, significant population of trapped Hydrogen from Ion Cyclotron Resonant Heating drives fishbone unstable, which is observed in self-consistent simulations of FAR3d. The obtained electromagnetic perturbation is afterwards introduced in TAPAS to integrate the trajectories of alpha particles in the inner core. It is concluded that there is significant global impact of the fishbone instability on the losses of alpha particles. Preliminary analyses have also been conducted to assess the impact of other instabilities, such as those excited by the passing population resulting in Toroidicityinduced Alfvén Eigenmodes, with frequencies larger than that of the fishbone. The results show that the effect of these modes on the confinement of alpha particles might be negligible