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P: Plasmaphysik

P 11: Dusty Plasmas and Low Temperature Discharges (Poster Session)

P 11.24: Poster

Donnerstag, 5. April 2001, 12:30–15:00, AT2

High resolution Doppler spectroscopy applied to an ECR plasma — • ¹, H. Kempkens², D. Hemmers², S. Meier², J. Uhlenbusch², and Z. Zhang³ — ¹ — ²Institut für Laser– und Plasmaphysik, Universität Düsseldorf — ³Institute of Physics, Chinese Academy of Sciences, Peking

Temperatures and drift velocities of the heavy particles in an ECR plasma have been measured by high resolution emission spectroscopy. From the Doppler width of the Argon ion line at 480.6 nm radial profiles of the temperature as a function of pressure and microwave power have been derived. The ion temperatures found between 2000 K and 9000 K are significantly higher than the temperatures of the neutrals, which are calculated from an energy balance and vary within 500 K to 1000 K. From the shift of the line center azimuthal drift velocities between 50 ms⁻¹ (detection limit) and 1800 ms⁻¹ (at 0.02 Pa) can be derived. This corresponds to a plasma rotation as a rigid body with a frequency up to 4 kHz. Within the uncertainties of the measurements an influence of an additional, radial magnetic field rotating with 264 Hz on the plasma rotation could not be detected. The Doppler profiles of the Balmer β line (486.1 nm) can be interpreted by the assumption of a hot component of the neutrals (4000 K to 10000 K) and a cold one (700 K to 1300 K). This work is supported by the DFG within the scope of the SFB 191.