It has been proposed that the Raman backscatter interaction in a plasma can be used to amplify ultra-intense laser pulses. To accomplish this, energy is transferred from a long drive pulse at frequency wpump to an intense seed pulse at frequency wseed, with a Langmuir plasma wave at frequency wp mediating the transfer; the frequencies are chosen to satisfy the resonant condition wp = wpump - wseed. Diffraction of the pulses limits the interaction length in a uniform plasma, and hence the energy transfer between the pulses. However in a parabolic plasma density channel it is shown, through two-dimensional particle-in-cell simulations, that such a plasma channel can be used to guide both the amplified and drive pulses over an interaction distance much greater than a diffraction length. The seed pulse is amplified by a factor of more than 200 in energy for pulses whose widths are matched to the channel size, and achieve a peak intensity of more than 6 × 1017 W/cm2. Unmatched pump pulses are seen to generate much smaller gain.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Raman backscatter