Electron parallel heat transport in the scrape-off layer using a particle-in-cell code

Abstract

Electron heat transport parallel to the magnetic field in the scrape-off layer plasma is investigated with the use of the particle-in-cell code PARASOL. Coulomb collisions are simulated correctly by a binary collision model. The heat flux is lost by radiation cooling, in addition to convection/conduction to the divertor plates. It is confirmed for the collisional case that the conductive heat flux is given by the Spitzer-Härm expression. For the long mean free path case, the conductive heat flux is limited to a factor αe of the free streaming value. It is found that αe is small (~0.1 of the sheath-limited value) for the low radiation condition, but becomes large (~1.0) for the high radiation condition.