X-rays as a diagnostic of laser plasma electron acceleration in cm-long capillary tubes.

摘要

In laser plasma based acceleration schemes [1], intense short-duration laser pulses interacting with under-dense plasmas expel electrons from the regions of high intensity and leave in their wake a.plasma wave. This wave is associated to large amplitude space charge electric fields used to accelerate relativistic electrons. In the non linear-regimes of laser wakefield, plasma electrons can be completely blown out of the intense laser region, and a fraction of the expelled electrons can be trapped in the accelerating potential of the plasma wave. In addition to the accelerating fields associated to the plasma wave, the accelerated electrons experience transverse fields. Thus these electrons can undergo strong transverse oscillations, or betatron oscillations, giving rise to the emission of synchrotron like radiation, which has been studied theoretically [2] and observed experimentally. [3].