Stark broadening by Lorentz fields in magnetically confined plasmas

Abstract

We examine atomic line shapes in a magnetized hydrogen plasma. The Lorentz electric field v × B present in the emitters' frame of reference yields a perturbation of the atomic energy levels, which is commonly referred to as a ‘motional’ Stark effect. This effect results in a broadening of the lines owing to the statistical repartition of the atoms' velocities. We address this line broadening mechanism with numerical simulations. It is shown that Balmer line shapes can be affected at plasma conditions relevant to magnetic fusion experiments. An application to the diagnostic of an atomic temperature is suggested and discussed within a line width analysis. The possibility for a modification of the Inglis–Teller limit, which provides an estimate of the principal quantum number of the last resolved line in a series, is also discussed.