Energetic electron generation by forward stimulated raman scattering using 0.35 and .053 micron laser light in a plasma

Abstract

This research investigates the use of high-powered lasers to produce 50-100 keV x-ray sources for applications for programs such as Stockpile Stewardship and nuclear weapons effects testing (NWET). To produce these x-ray sources requires irradiating targets with intense laser light to efficiently generate high-energy electrons. Stimulated Raman scattering (SRS) of intense laser light produces electron plasma waves, which in turn generate high-energy electrons. To make a high-energy x-ray source, the maximization of this laser- driven instability is desired. Using computer simulations, we show that SRS can be driven by using a combination of frequency-tripled and a 'seed' beam of frequency doubled Neodymium laser light in a plasma of the appropriate density. Electron plasma waves with a high phase velocity are produced, which trap electrons and accelerate them to high energy. These energetic electrons will in turn generate high energy x-rays via collisions with nearby dense material. By adjusting the angle between the 0.35 micrometers and 0.53 micrometers laser beams, the characteristic temperature of the heated electrons (and the x-rays) can be varied. We show one and two-dimensional simulations and illustrate the important role that laser-driven ion fluctuations play.