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Applied Plasma Physics and Fusion Energy Seminar Series

Fall 2002

Tuesday, 3:30-4:30 PM in 479 EBU-II

November 26

Internal Structure and Expansion Dynamics of Laser Ablated Plumes

S. S. Harilal
UC San Diego


The interaction of laser-ablated plumes with background gases is currently receiving considerable attention because of its importance in the basic and applied research fields. The effect of ambient gas on the expansion dynamics of the plasma generated by laser ablation of an aluminum target has been investigated. The diagnostic tools include fast photography and space and time resolved emission spectroscopy. The expansion behavior of the plasma is studied over a wide range of ambient air pressure. Free expansion, plume splitting and sharpening, hydrodynamic instability and stagnation of the plume are observed at different pressure levels. Combining imaging together with time resolved emission diagnostics, a triple structure of the plume is observed. The expansion of the plume front is compared with various expansion models and found to be generally in good agreement.

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