CASPER Seminar Series Presents - Dr. Volodymyr Nosenko, DLR/CASPER

DateApril 28, 2017Time2:30 - 3:30 pm
LocationBaylor Sciences Building D.110
Description

Dr. Volodymyr Nosenko
Associate Director of Research, CASPER, Baylor University
Institut fu╠...r Materialphysik im Weltraum, Deutsches Zentrum fu╠...r Luft- und Raumfahrt,
Forschungsgruppe Komplexe Plasmen, D-82234 We├čling, Germany

Title:
Enhanced Dynamics of Particles in Complex Plasmas: The Role of Ion-wake Effect

Abstract: Two-dimensional (2D) plasma crystals are popular model systems to study various phenomena such as waves, phase transitions, and transport phenomena, in real time and at the level of individual particles. However, careful attention is required to clearly differentiate between the generic and plasma-related phenomena which are peculiar to plasma crystals. The latter, for instance, may include channeling of upstream extra particles, mode-coupling instability (MCI), or particle pairing. Vertical pairs of particles can form in a 2D plasma crystal spontaneously or after a sudden drop of the neutral gas pressure. Pairs of particles which were spinning around their axis were recently observed experimentally. Such spinning pairs, or torsions are driven by the vertical flow of ions in the plasma sheath where the particles are suspended. Their formation can be stimulated by reducing the discharge power at constant neutral gas pressure. At higher gas pressures, torsions spontaneously form below a certain power threshold. However, at lower gas pressures their formation is preceded by MCI. The essential role of ion wakes in the above mentioned phenomena will be discussed.

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