Magnetic-field distortion near an ablating hydrogen pellet

Abstract

A model is formulated to describe the distortion of the magnetic field near an ablating solid hydrogen pellet in a plasma. The resistive, collision-dominated ablation cloud expands across the magnetic field. The originally straight magnetic field lines threading the pellet and the ablatant convect outward with the flow and at the same time diffuse inward, giving rise to a rarefaction of the field lines near the pellet. This effect reduces the incident electron energy flux to the ablatant. The resulting modest increase in pellet life-time implies a more favourable outlook for refuelling tokamak reactors by pellet injection.