Cerenkov radiation from a magnetized plasma: a diagnostic for PBWA experiments

In the plasma beat acceleration scheme, the ponderomotive force of a two-frequency laser pulse resonantly drives a large amplitude (E^es≈3 GV/m) relativistic electrostatic plasma wave. The electro-static wave does not couple to the vacuum modes and its energy is dissipated in the plasma. With a static magnetic field B₀z applied perpendicularly to the laser beam propagation axis x, the two-frequency laser pulse couples to the L branch of the XO mode of the magnetized plasma through Cerenkov radiation. The electromagnetic component of the XO mode couples to the vacuum mode. The plasma wave is not affected by the transverse magnetic field, and measuring the characteristic of the emitted radiation thus provides an in-situ diagnostic for the beat-wave-excited accelerating structure (amplitude, phase, and damping for example). Additionally, the mechanism of interest is a possible source for a gigawatt terahertz radiation source