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P: Fachverband Plasmaphysik

P 15: Poster: Diagnostik

P 15.6: Poster

Wednesday, April 1, 2009, 17:30–19:30, Foyer des IfP

A diagnostic supersonic helium beam for 28 GHz ECRH operation on WEGA — •Daniel Andruczyk, Maciej Krychowiak, Matthias Otte, and Eric Müller — Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, EURATOM Association, Wendelsteinstr. 1, 17491 Greifswald, Germany

Recently a 10 kW, 28 GHz electron cyclotron resonant microwave heating system has been installed and used on WEGA. Using electrostatic Bernstein wave heating via a mode conversion process, the temperature achieved is beyond a few 10 eV and the density between 10¹⁸ − 10¹⁹ m⁻³. A diagnostic Supersonic helium beam (SHeB), in conjunction with a collisional radiative model (CRM), has been developed to provide a non-intrusive method of measuring the electron density and temperature in the plasma. The beam is excited by the electrons in the plasma and the emission of certain wavelengths, together with a line ratio technique, used to determine the plasma parameters. Since the excitation is done by the plasma the emission is a direct measurement of the plasma parameters. A nozzle-skimmer design has been used to produce a thin ( 20 mm width at plasma centre) beam for good spatial resolution together with a 10 channel photo-multiplier and optical fibre system to measure the parameters radially through the plasma. The SHeB will be used to acquire information for high temperature and density argon and hydrogen plasmas. This poster will give an overview of the beam development and the first measurements to come from it.