Experiments on laser driven beatwave acceleration in a ponderomotively formed plasma channel

Abstract

A 10 ps long beam of 12 MeV electrons is externally injected into a ϳ3-cm long plasma beatwave excited in a laser ionized hydrogen gas. The electrons have been accelerated to 50 MeV with a gradient of ϳ1.3 GeV/m. It is shown that when the effective plasma wave amplitude-length product is limited by ionization-induced defocusing ͑IID͒, acceleration of electrons is significantly enhanced by using a laser pulse with a duration longer than the time required for ions to move across the laser spot size. Both experiments and two-dimensional simulations reveal that, in this case, self-guiding of the laser pulse in a ponderomotively formed plasma channel occurs. This compensates for IID and drives the beatwave over the longer length compared to when such a channel is not present.

Mid-infrared lasers for energy frontier plasma accelerators

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Status of the Polarized Nonlinear Inverse Compton Scattering Experiment at Ucla

“…When the beam electrons are incident on the crystal oriented at 45 o , a semiconductor plasma is formed which is opaque to the 10.6 ȝm laser light. By measuring the transmitted intensity of the laser, the relative timing between the beams is revealed and allows for tuning of the arrival time at the IP [7].…”

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“…By measuring the transmitted intensity of the laser, the relative timing between the beams is revealed and allows for tuning of the arrival time at the IP [7]. The two beams must also be synchronized in time at the IP.…”