Electron acceleration by a tightly focused laser pulse in an ion channel

We examine the electron acceleration by tightly focused radially polarized laser beam in a preformed ion channel. The tight focusing and polarization of laser beam takes the advantage of extremely intense and asymmetric fields. The longitudinal electric field component at the beam center helps in trapping of electrons. For effective acceleration, the preformed ion plasma channel behaves as an applied external magnetic field. The electrostatic space charge field of this preformed ion channel helps in trapping of electrons and confined them to the accelerating phase. The gain in the energy of the electron is due to the fact that the radial component of electric field becomes zero on the propagation axis and only longitudinal component survives which accelerate the electrons in the longitudinal direction to high energy. The electrostatic space charge field assists in confining the motion of electrons from transverse oscillation and injects them to accelerating field which causes a resonance between electric field of laser and electrons. Because of combined role of tightly focused radially polarized laser and ion channel, the electrons can gain energy of the order of GeV