Hannover 2010 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 8: Poster: Low Temperature Plasmas I
P 8.23: Poster
Dienstag, 9. März 2010, 16:00–18:00, Lichthof
Experiments with electron and ion beams in a linear plasma device. — •Christopher Rapson1, Olaf Grulke1,2, and Thomas Klinger1,2 — 1MPI for Plasma Physics, EURATOM Association, Greifswald — 2Ernst-Moritz-Arndt University, Greifswald
Ion and electron beams provide a source of free energy to excite density and potential fluctuations in plasmas. Particularly in space plasmas, but also in the laboratory, beam-plasma instabilities play a decisive role in the plasma dynamics. In this contribution, results of investigations using simulation and laboratory experiments are presented, for both electron and ion beams. These kinetic phenomena are investigated using PIC simulations, which yield the dispersion relation and spatio-temporal evolution of the fluctuations for a wide range of beam and plasma parameters. Experiments are performed in the linear experiment VINETA (n∼1016 m−3, Te∼3 eV). For the electron beam, results show a good agreement between oscillation frequency and electron plasma frequency, as determined from Langmuir probe measurements. However, it is observed that the oscillation frequency is independent of the local density, and does not reflect the density profile. Complementary to the electron beam investigation, a potassium ion beam (K+) has been injected into the argon plasma. Measurements with an ion energy analyser and a Langmuir probe show that the ion beam driven fluctuations evolve on the much slower ion acoustic time scale.