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P: Fachverband Plasmaphysik

P 13: Poster Session - Diagnostics

P 13.15: Poster

Tuesday, March 18, 2014, 16:30–18:30, SPA Foyer

Polarization of hard bremsstrahlung as an efficient diagnostic tool for hot plasmas — •Stanislav Tashenov¹, Csilla Szabo-Foster², Paul Indelicato², and Alexandre Gumberidze³ — ¹Physics Institute, Heidelberg University, Germany — ²Laboratoire Kastler Brossel, Ecole Normale Supérieure, CNRS, Université Pierre et Marie Curie-Paris 6, France — ³ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany

Plasma polarization diagnostics is a mature technique which is sensitive to plasma anisotropies. It was applied at hot laboratory plasmas such as fusion plasmas. It is also planned to be used for astrophysics observations. In these techniques x-ray transition lines are observed with polarization-sensitive detectors based on the Bragg reflection. The collision processes such as electron-impact excitation, ionisation and recombination leave the ion in the excited and aligned state and its decay produces polarised x-rays. The polarization properties of such x-rays differ from process to process and the total degree of polarization is often reduced to a few percents. Here we introduce a new technique of polarization diagnostics which is based on bremsstrahlung radiation detected with a Compton polarimeter. This technique is simpler yet more efficient than the once mentioned before. In a test measurement at an Electron Cyclotron Resonance Ion Trap with 15 keV plasma we observed 70% polarization of 30-60 keV x-rays. Since bremsstrahlung is the dominant x-ray emission mechanism the intensity of these x-rays allows for a highly efficient diagnostic technique.