Electron heat conduction coefficient at internal disruption in low-q DIVA plasmas

Abstract

Electron temperature and density profiles are measured by Thomson scattering of ruby laser light in a low-q DIVA plasma; the profiles are strongly affected by internal disruption. The effective electron conduction coefficients χ_ep at the moment of internal disruption are calculated on the basis of the diffusion equation. – The average value of χ_ep outside the q = 1 singular surface r_D, 7.2 × 10⁴cm²s⁻¹ is much larger than that expected for the base discharge, which implies that the internal disruption substantially enhances the thermal transport throughout the region r_Dep(r) profile inside the q = 1 surface is approximated by the equation χ_ep(r)= 1.4 × 10⁵ × (1–(r/11)^1.5)cm²s⁻¹ at 0≤r≤r_D.