Coherent inverse Compton scattering with attosecond electron bunches   accelerated and compressed by radially polarized laser pulses
  We present a study of direct laser driven electron acceleration and scaling of attosecond bunch compression in unbound vacuum. Simple analytical expressions and detailed three-dimensional numerical calculations including space charge reveal the conditions for compression to attosecond electron sheets. Intermediate emittance minima suitable for brilliant x-ray generation via coherent inverse Compton scattering (ICS) are predicted. We verify the coherent emission properties of the resulting x-ray fields and demonstrate feasability for realistic laser parameters. 
Alexander Sell, Franz X. K\"artner
physics.acc-ph physics.optics