Particle acceleration and coherent radiation by subcycle laser pulses

Electron acceleration by subcycle laser pulses is studied. It is shown in the particle simulations that the irradiation of an intense subcycle pulse on a thin plasma layer gives rise to a pickup of all plasma electrons on the spot and accelerate them to lead to a formation of the high-energy bunched electrons. The condition of generating coherent synchrotron radiation from the bunched electrons is estimated to apply to a bright X-ray source.