The amplitude, growth and decay rate of a self modulated wakefield was characterized by employing a femtosecond pump-probe experiment based on forward, collective Thomson scattering. A λ = 1 μm, τ = 400-fs laser pulse was focused onto a supersonic helium gas jet whose neutral density varied linearly with backing pressure. The plasma wave lifetime was probed by splitting off a small portion of the infrared laser pulse. The measured exponential rise time of the wakefield is in agreement with that expected from the of forward Raman scattering (FRS) instability. Since the total energy of the accelerated electron beam is approximately equal to the energy in the plasma wave, the measured exponential decay rate is consistent with the nonlinear Landau damping.
|Number of pages||1|
|State||Published - 1997|
|Event||Proceedings of the 1997 Conference on Quantum Electronics and Laser Science, QELS - Baltimore, MD, USA|
Duration: 18 May 1997 → 23 May 1997
|Conference||Proceedings of the 1997 Conference on Quantum Electronics and Laser Science, QELS|
|City||Baltimore, MD, USA|
|Period||18/05/97 → 23/05/97|