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Open Access research with a European policy impact...

The Strathprints institutional repository is a digital archive of University of Strathclyde's Open Access research outputs. Strathprints provides access to thousands of Open Access research papers by Strathclyde researchers, including by researchers from the European Policies Research Centre (EPRC).

EPRC is a leading institute in Europe for comparative research on public policy, with a particular focus on regional development policies. Spanning 30 European countries, EPRC research programmes have a strong emphasis on applied research and knowledge exchange, including the provision of policy advice to EU institutions and national and sub-national government authorities throughout Europe.

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Effects of energy absorption on Raman amplification in plasma

Ersfeld, Bernhard and Farmer, John and Raj, Gaurav and Jaroszynski, Dino A. (2009) Effects of energy absorption on Raman amplification in plasma. In: Conference on Harnessing Relativistic Plasma Waves as Novel Radiation Sources From Terahertz to X-Rays and Beyond, 2009-04-21 - 2009-04-23.

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Abstract

Stimulated Raman backscattering in plasma has been suggested as a way to amplify short laser pulses to intensities not limited by damage thresholds as in chirped pulse amplification using conventional media. Energy is transferred between two transverse electromagnetic waves, pump and probe, through the parametric interaction with a longitudinal Langmuir wave that is ponderomotively excited by their beat wave. The increase of the plasma temperature due to collisional absorption of the pump wave modifies the dispersion of the Langmuir wave: firstly, its resonance frequency rises (Bohm-Gross shift), and secondly, Landau damping sets in. The frequency shift acts in a similar way to a chirp of the pump frequency, or a density ramp: different spectral components of the probe satisfy the resonance condition at different times. This limits their growth, while increasing the bandwidth of the amplifier, thus leading to superradiant amplification. Landau damping may shorten the probe pulse, but reduces the amplification efficiency. We investigate these effects analytically and using numerical simulations in order to assess their importance in experimental demonstrations, and the possibility of applications.