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UP: Fachverband Umweltphysik
UP 12: Atmosphäre - Labor
UP 12.1: Hauptvortrag
Donnerstag, 20. März 2014, 09:30–10:00, MAG 100
Laser filament induced secondary ice multiplication under cirrus cloud conditions — Thomas Leisner1, Denis Duft1, Harald Saathoff1, Martin Schnaiter1, Stefano Henin2, Kamil Stelmaszczyk3, Massimo Petrarca2, Raphaëlle Delagrange2, Zuoqiang Hao3, Johannes Lüder1, Yannick Petit2, Philipp Rohwetter3, Jérôme Kasparian2, Jean-Pierre Wolf2, and •Ludger Wöste3 — 1Institute for Meteorology and Climate Research, KI, 76131 Karlsruhe, Germany — 2GAP, Université de Genève, CH 1211 Genève 4, Switzerland — 3Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
The interaction of artificial plasma channels with water and ice clouds was investigated in the large cloud simulation chamber AIDA. Under the conditions of a typical storm cloud, where ice and supercooled water coexist, no influence of the plasma channels on the ice formation could be detected. Under conditions typical for thin cirrus ice clouds however, the plasma filaments induced a surprisingly strong effect of ice multiplication. Here, the laser action led to a strong enhancement of the total ice particle number density in the chamber by up to a factor of 100, even though only a 10-9 fraction of the chamber volume was exposed to the laser filaments. The newly formed ice particles quickly reduced the water vapor pressure to ice saturation thereby increasing the cloud optical thickness by up to three orders of magnitude. A model relying on the complete vaporization of ice particles in the laser filament and the condensation of the resulting water vapor on plasma ions reproduces our experimental findings [1].