Electron and ion stagnation at the collision front between two laser produced plasmas
Hough, Pádraig, McLoughlin, Conor, Kelly, Thomas J., Hayden, PatrickORCID: 0000-0002-4314-4560, Harilal, Sivanandan S., Mosnier, Jean-Paul and Costello, John T.ORCID: 0000-0003-4677-9999
(2009)
Electron and ion stagnation at the collision front between two laser produced plasmas.
Journal of Physics D: Applied Physics, 42
(5).
ISSN 1361-6463
We report results from a combined optical interferometric and spectrally resolved imaging study on colliding laser produced aluminium plasmas. A Nomarski interferometer was used to probe the spatio-temporal distribution of electron densities at the collision front. Analysis of the resulting interferograms reveals the formation and evolution of a localized electron density feature with a well-defined profile reminiscent of a stagnation layer. Electron stagnation begins at a time delay of 10 ns after the peak of the plasma generating laser pulse. The peak electron density was found to exceed 10^19 cm^−3 and the layer remained well defined up to a time delay of ca 100 ns. Temporally and spectrally resolved optical imaging was also undertaken, to compare the Al^+ ion distribution with that of the 2D electron density profile. This revealed nascent stagnation of singly charged ions at a delay time of 20 ns. We attribute these results to the effects of space charge separation in the seed plasma plumes.
Metadata
Item Type:
Article (Published)
Refereed:
Yes
Uncontrolled Keywords:
lasers; plasmas; stagnation layer; colliding plasmas; electron density profile; ion distribution;