Berlin 2014 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 8: Diagnostics I

P 8.1: Hauptvortrag

Dienstag, 18. März 2014, 10:30–11:00, SPA HS201

Coherence imaging spectroscopy: A new method for measuring plasma dynamics — •Oliver P. Ford¹, John Howard², Matthias Reich¹, Jakob Svensson¹, and Robert Wolf¹ — ¹Max-Planck-Institut für Plasmaphysik, Greifswald/Garching, Germany — ²Plasma Research Laboratory, Australian National University, Canberra, Australia

In mangetic confinement fusion plasmas, diagnosis of the magnetic field is of particular interest as it is critical to the efficiency and stability of the plasma confinement but is created partly from unknown currents in the plasma itself. High plasma temperatures restrict core diagnostics to observation of emitted radiation and magnetic field direction is typically inferred through the polarisation of Hydrogen Balmer-α emission, split by the Stark and Zeeman effects. This simultaneous spectroscopy and polarimetry usually requires complex hardware for a small number of measurements. Coherence imaging is a new technique which, with a few small crystal plates and a CCD camera, acquires images of the plasma, modulated with interference patterns that encode the spectral and polarisation information. These diagnostics are substantially simpler, more flexible and provide an order of magnitude more data than traditional systems. The basic principle of coherence imaging will be explained and measurements from the prototype Imaging Motional Stark Effect (IMSE) diagnostic recently installed on the ASDEX Upgrade Tokamak will be presented. Additionally, ion temperature and velocity measurements by Doppler coherence imaging on other small plasma devices will be presented.