Stochastic Processes Applied to the Spectroscopic Diagnostic of Hydrogen in Edge Plasmas

Stochastic processes may be used as an efficient model for the line shapes affected by Stark effect in edge plasma conditions. We check the accuracy of this approach on the Lyman γ line of hydrogen perturbed by ions only. We also use a stochastic process to investigate the effect of plasma oscillations on a line shape. Our model assumes that Langmuir waves are a sequence of oscillating electric fields changing their amplitude and phase according to an exponential waiting time distribution. The possible effects of Langmuir waves on the Lyman α Stark profile are discussed in edge plasma conditions. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)