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<div><font color="#000080" size="6"><b>Old Dominion University</b></font></div>
<div><font color="#000080" size="6"><b>Department of Physics</b></font></div>
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<div><font color="#4BACC6" size="5"><b>Fall Colloquium Series</b></font></div>
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<div><font color="#17365D" size="5"><b>Tuesday November 9, 2010</b></font></div>
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<div><font color="#4BACC6" size="5"><b>"Laser Wakefield Acceleration at Low Density in the Blowout Regime"</b></font></div>
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<font color="#1F497D" size="5"><b>Dr. Joe Ralph</b></font></div>
<div><font color="#1F497D" size="5"><b>Lawrence Livermore National Laboratory</b></font></div>
<div><font color="#1F497D" size="5"><b>NIF/Photon Sciences</b></font></div>
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<div>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 10<font size="1"><sup>18</sup></font> to 10<font size="1"><sup>19 </sup></font>cm<font size="1"><sup>-3</sup></font>.
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.</div>
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<div><font size="4">Presentation: OCNPS 200 @ 3:00 pm</font></div>
<div><font size="4">Refreshments: Atrium @ 2:30 pm</font></div>
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<div><font size="4">More details at <a href="http://www.physics.odu.edu">
http://www.physics.odu.edu</a></font></div>
<div><font size="4">All are Welcome<font size="3">!</font></font></div>
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