Ultra-dense electron beams and relativistic electron mirror for production of intense brilliant x-rays by coherent reflection

When a laser pulse with an intensity beyond 10¹⁸ W/cm² is focused onto a foil that has a thickness of several nanometers only, the electrons are pushed forward by the enormous light pressure of several Gigabars. Typically, the ions can be dragged along and accelerated to high energies (A.2.3). However, when the foil is even thinner, the laser is able to rip off the electrons and accelerate them. For a very short time, the electron bunch is maintaining its high density before it expands due to Coulomb explosion.
In this project we study the dynamics of the electrons in such ultra-thin foils by characterisation of the electrons that are emitted during the interaction with the laser. Complemented by electron spectrometers it is envisioned to use a short laser pulse to probe the interaction, for example via measurement of Thomson back-scattered light. Moreover, the high density and short duration of the electron bunch(es) may promise to become an attractive source of radiation with a spectrum reaching up to the X-ray regime.