Mainz 1997 – wissenschaftliches Programm
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P: Plasmaphysik
P 13: Postersitzung I
P 13.62: Poster
Dienstag, 4. März 1997, 16:00–18:00, Foyer
On the electron kinetics in periodic electric fields as occurring in moving striations — •Yu.B. Golubovski1, I.A. Porokhova1, F. Sigeneger2, and R. Winkler2 — 1Institute of Physics, St. Petersburg University, Russia — 2Institut für Niedertemperatur-Plasmaphysik Greifswald
In dc plasmas of inert gas glow discharges self-excited spatially periodic structures, known as striations or ionization waves, occur in the region of medium electric field strengths. These structures are characterized e.g. by a strong modulation of the electric field and the electron velocity distribution function (EVDF). The determination of the electron behaviour under such nonlocal conditions requires the solution of the inhomogeneous electron Boltzmann equation. By solving this equation it has been recently found that periodic structures in the EVDF are excited too if a spatially limited disturbance in the EVDF or in the field initiates, under the impact of a homogeneous electric field, a spatial relaxation process of the electrons into a homogeneous state. A comparison of the period lengths of both phenomena clearly indicates their narrow connection. Using the spatial potential course measured in striations of a Neon plasma, the establishment of the electron component into its periodic state is investigated. A detailed comparison of the EVDF calculated for the periodic state with corresponding experimantal results on the EVDF in striations will be presented. Furthermore the complex behaviour of the electrons in such strongly modulated fields will be analysed and discussed.