Greifswald 2009 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 9: Poster: Niedertemperaturplasmen
P 9.8: Poster
Dienstag, 31. März 2009, 17:30–19:30, Foyer des IfP
Experimental investigations of electron- and ion- beam driven instabilities — •Christopher Rapson1, Olaf Grulke1,2, and Thomas Klinger1,2 — 1MPI for Plasma Physics, EURATOM Association, Greifswald — 2Ernst-Moritz-Arndt University, Greifswald
Plasma instabilities due to excitation by beams of electrons or ions have been observed in space and laboratory plasmas, and are relevant for a variety of dynamical phenomena in e.g. interstellar plasmas, particle accelerators and fusion plasmas. Beam particles can amplify plasma waves and large amplitude waves act in turn on the particles. Depending on the beam velocity and particle species different types of instabilities can be formed.
Electron and ion beams have been injected into an argon plasma (n=1015 m−3, Te=4 eV) in the linear plasma device VINETA. Beam densities are both 1% of the background density and particle energies correspond to electron thermal and ion acoustic velocities, respectively. The associated plasma dynamics is investigated with Langmuir probes and emissive probes for density and potential fluctuation measurements, respectively. The spatiotemporal evolution of the beam driven instabilities is reconstructed and compared to initial PIC simulation results.