Frankfurt 2006 – wissenschaftliches Programm

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SYIF: Intense field interaction with molecules and clusters

SYIF 2: Intense field interaction with molecules and clusters 2

SYIF 2.4: Hauptvortrag

Freitag, 17. März 2006, 18:00–18:30, HV

New Perspectives Arising from Femtosecond Plasma Channels in Air. — •Ludger Woeste — Freie Universitaet Berlin, Institut fuer Experimentalphysik, Arnimallee 14, 14195 Berlin

When powerful femtosecond laser pulses interact with air, extended plasma channels can be formed. Their extraordinary physical properties open fascinating perspectives for the investigation of the atmosphere. The emitted white-light allows - for example - to retrieve information about the atmospheric composition including trace gases. On the other hand, non-linear light emission from the aerosol allows its remote elementary analysis, which so far is not possible by other optical methods. In addition, the phenomenon of radiation-induced nucleation can be used to withdraw information about optical super-saturation, which is also an optically inaccessible parameter so far. The electrical properties of the plasma channels open besides that fascinating perspectives with regard to lightning research. In the presentation the following aspects will be discussed:

• Conventional air monitoring methods and their limits

• Principle of the femtosecond LIDAR

• Formation and propagation of plasma channels in air

• Absorption measurements on atmospheric trace gases

• Measurements of the aerosol

• Electrical properties

• Outlook