On the Pointing Angle of Electron Beams from Laser Wakefield Accelerators

Laser wakefield accelerators offer electron beams which could be useful for many applications. However, the problem of stabilizing the electron beam parameters has not been resolved yet. Here, we propose a method to minimize the electron beam pointing and report the generation of a relativistic electron beam with a stabilized pointing angle of 2 mrad (rms). This was achieved by using asymmetric non-relativistic laser pulses interacting with low-density helium gas jet. In such a weakly-nonlinear regime, symmetric laser pulses were neither able to generate reproducible nor stable electron beams. Thus, we propose asymmetric laser pulses for generating electron beams having stable and small pointing angles from laser-plasma accelerators.