Observation of spatial asymmetry of THz oscillating electron plasma wave in a laser wakefield

The asymmetric spatial distribution of electron density perturbation is obs erved by using a frequency-domain interferometry technique. The wake amplit ude of the outside bump is enhanced by the elliptical distribution of the p ump laser pulse. This asymmetry can be explained with a two-dimensional ana lytical model expanded from cylindrically symmetric linear theory.