Motional stark effect measurements of the local magnetic field in high temperature fusion plasmas

Abstract

The utilization of the Motional Stark Effect (MSE) experienced by the neutral hydrogen or deuterium injected into magnetically confined high temperature plasmas is a well established technique to infer the internal magnetic field distribution of fusion experiments. The different properties of the Stark multiplet allow inferring, both the magnetic field strength and the orientation of the magnetic field vector. Besides recording the full MSE spectrum, several types of polarimeters have been developed to measure the polarization direction of the Stark line emission. To test physics models of the magnetic field distribution and dynamics the accuracy requirements are quite demanding. In view of these requirements, the capabilities and issues of the different techniques are discussed, including a newly developed Imaging MSE system which has been tested on the ASDEX Upgrade tokamak. Show more