Contributo in atti di convegno, 2022, ENG, 10.1088/1742-6596/2397/1/012004

Stability of a weakly collisional plasma with runaway electrons

Grasso, Daniela; Borgogno, Dario; Singh, Lovepreet; Subba, Fabio

Istituto Dei Sistemi Complessi, CNR, Dipartimento di Energia, Politecnico di Torino, Torino, Italy; NEMO Group, Dipartimento Energia, Politecnico di Torino, Torino, Italy

We investigate the problem of the tearing stability of a post-disruption weakly collisional plasma where the current is completely carried by runaway electrons. We adopt here a two fluid model which takes into account also ion sound Larmor radius and electron inertia effects in the description of the reconnection process. In the past, it has been demonstrated in [Helander et al. Phys. Plasmas 14, 12, (2007)] that in the purely resistive regime the presence of runaway electrons in plasma has a significant effect on the saturated magnetic island width. In particular, runaway electrons generated during disruption can cause an increase of 50% in the saturated magnetic island width with respect to the case with no runaway electrons. These results were obtained adopting a periodic equilibrium magnetic field that limited the analysis to small size saturated magnetic islands. Here we present our results to overcome this limitation adopting a non-periodic Harris' type equilibrium magnetic field. Preliminary results on the effects of the ion sound Larmor radius effects will also be presented

2022 Joint Varenna-Lausanne International Workshop on the Theory of Fusion Plasmas, Varenna-Lausanne 202, Varenna, 12 - 16 september 2022

Keywords

Collisionless plasmas; Electrons; Magnetic fields; Magnetoplasma; Plasma stability; Two phase flow

CNR authors

Borgogno Dario, Grasso Daniela

CNR institutes

ISC – Istituto dei sistemi complessi