Bochum 2002 – scientific programme

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P: Plasmaphysik

P 22: Poster: Magnetische Fusion, Plasmadiagnostik, Dichte Plasmen

P 22.10: Poster

Tuesday, March 19, 2002, 17:40–18:40, HZO Foyer

Spatially resolved determination of the cross-sectional distribution of heavy particles in an asymmetrical arc discharge by resonant digital speckle pattern interferometry — •Martin Hipp, Alexander Morozov, and Theo Neger — Institut für Experimentalphysik, Technische Universität Graz, Petersgasse 16, A-8010 Graz, Austria

Digital Speckle Pattern Interferometry (DSPI) is utilized to investigate the sodium ground state density in a distinct cross-section of a Na-seeded free burning asymmetrical arc discharge. Simultaneous recording of projections is realized using six light sheets through the plasma at equal angular separations. These projections are coupled with help of a special holographic-optical element, serving also as a spectral filter for elimination of direct plasma radiation. To detect the density of the seeded sodium, a ring dye laser scans the NaD₂-line during continuous measurement of phase changes by temporal phase shifting DSPI. The integral resonant phase changes of the six directions are then fed to a tomographical reconstruction algorithm. By fitting the results of different wavelengths with the Voigt profile, the number density of the ground state sodium atoms in the discharge are obtained.