Indexed on: 25 Oct '19Published on: 23 Oct '19Published in: arXiv - Physics - Plasma Physics
We investigate a method to generation of $\gamma$ ray photons in collision of an ultrahigh intensity laser pulse with a laser-wakefield accelerated electron beam. We consider the composed target of a homogeneous underdense preplasma in front of an ultrathin solid foil. By using of two dimensional particle-in-cell simulations, we show that the electrons in the underdense plasma are trapped and accelerated by the laser wakefield. When the laser pulse is reflected by the thin solid foil, the wakefield accelerated electron beam continue to move forward and passing through the target almost without the influence of the reflected laser pulse and the foil. Consequently, two groups of $\gamma$ ray flashes are generated by the wakefield accelerated electron beam interacting with the reflected laser pulse in front of the foil as well as interacting another counter propagating pitawatt laser pulse in the vacuum area behind the foil. The dependence of the emission on the preplasma parameters and driving laser polarization are systematically studied. The use of produced $\gamma$ rays in future QED research is discussed.