Impurity influx model of fast tokamak disruptions

Abstract

The high plasma resistance observed in tokamak disruptions with a very rapid current decay is attributed to cooling by a rapid influx of neutral atoms from the wall or limiter. It is suggested that this influx proceeds as a dense localized cloud expanding from the edge to the centre of the plasma. The result of such a cooling, with carbon as the limiting material, is a drop in temperature to approximately 4 eV and an increase in electron density by an order of magnitude