[loacl physicists] Colloquium Announcement 11/9/2010 (Dr. Joe Ralph)

[Malin, Delicia M.]

[X]




Old Dominion University
Department of Physics

Fall Colloquium Series

Tuesday November 9, 2010

"Laser Wakefield Acceleration at Low Density in the Blowout Regime"


Dr. Joe Ralph
Lawrence Livermore National Laboratory
NIF/Photon Sciences


In a laser wakefield accelerator, an ultrashort, relativistically intense laser pulse (a0>2) drives an electron plasma wave of sufficient amplitude to trap and accelerate electrons to very high energies in short distances.  Such "table-top" accelerators have the potential to bring high-energy, high quality electron beams to universities, hospitals and research facities.  Recently, several advances in the theory and simulations of the blowout laser wakefield accelerator regime have produced a model describing the balance between the nonlinear optical effects of self-focusing and local pump depletion.   An overview of these advances will be presented with experimental and simulation results.  In addition, a review of recent experimental campaigns performed using mixed gas and pure Helium targets ranging in length from 3 mm to 14 mm produced electron energies beyond 700 MeV in a monoenergetic beam and beyond 1.4 GeV in a tail of electrons.  To achieve such high-energy electrons, a 200 TW 60 fs laser pulse was focused to a spot size of 15 microns and propagated through underdense plasmas with densities ranging from 1018 to 1019 cm-3.  Current experimental work focuses on extending the interaction length and increasing the energy as well as reducing the energy spread of the GeV electrons by combining an injection stage with an acceleration stage.  A portion of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and a Department of Energy Grant No. DEFG02-92ER40727 and was partially funded by the Laboratory Directed Research and Development Program under tracking code 06-ERD-056.



Presentation: OCNPS 200 @ 3:00 pm
Refreshments: Atrium @ 2:30 pm

More details at http://www.physics.odu.edu
All are Welcome!


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