Stuttgart 2012 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 3: Correlation dynamics in plasmas and clusters I

A 3.3: Hauptvortrag

Montag, 12. März 2012, 11:30–12:00, V47.03

Quantum and classical measures of molecular ultracold plasma dynamics — Jonathan Morrison, Hossein Sadeghi, Markus Schulz-Weiling, Donald Kelloway, Nicolas Saquet, and •Edward Grant — University of British Columbia, Vancouver, Canada

Ultracold plasmas offer laboratory access to an important regime of ionized gases in which moderate densities combine with very low ion and electron temperatures to approach conditions of strong Coulomb coupling. Many examples have been studied in atomic systems under conditions of laser cooling in magneto-optical traps. Work in our laboratory has developed an alternative approach using samples cooled in a seeded supersonic molecular beam. This method yields much higher charged particle densities, and appears to attain comparable or even lower electron and ion temperatures, elevating the prospect of strong coupling. Using a beam, we can readily form plasmas composed of molecular ions. Experiments together with model calculations show that molecular effects play a significant role in plasma evolution. For example, ultracold plasmas show promise as bright sources of electrons. Such utility depends on their properties of expansion and decay. This talk presents new results on the ultracold plasma formed by exciting NO in a molecular beam. Aided by model calculations, we show how molecular processes, including dissociative recombination and collision-induced internal conversion, act to effect the spatial and energetic relaxation of the plasma.