Gamma-ray emission in near critical density plasmas at laser intensities of 10(21) W/cm(2)

摘要

We study synchrotron radiation emission from laser interaction with near critical density (NCD) plasmas at intensities of 10(21) W/cm(2) using three-dimensional particle-in-cell simulations. It is found that the electron dynamics depend on the laser shaping process in NCD plasmas, and thus the angular distribution of the emitted photons changes as the laser pulse evolves in space and time. The final properties of the resulting synchrotron radiation, such as its overall energy, the critical photon energy, and the radiation angular distribution, are strongly affected by the laser polarization and plasma density. By using a 420 TW/50 fs laser pulse at the optimal plasma density (similar to 1n(c)), about 10(8) photons/0.1% bandwidth are produced at multi-MeV photon energies, providing a route to ultraintense, femtosecond gamma ray pulses. (C) 2015 AIP Publishing LLC.