Dependence of resistivity gradient guiding of laser-driven relativistic electron beams on laser intensity and duration

A laser-driven relativistic electron beam (REB) has a large beam divergence. For the efficient heating of material by REB, for example, core heating in fast ignition, beam guiding from its generation point to the heating material to be heated by suppressing spatial divergence in a perpendicular direction to keep its intensity sufficiently high is indispensable. We evaluated the dependences of the REB guiding performance in the resistivity gradient guiding scheme [A. P. L. Robinson and M. Sherlock, “Magnetic collimation of fast electrons produced by ultraintense laser irradiation by structuring the target composition,” Phys. Plasmas 14, 083105 (2007)] on laser intensity and duration, from the present petawatt laser parameters to the fast ignition-relevant laser parameters, in terms of the temperature dependence of resistivity and energy deposition of the REB. The REB transport simulations in solid materials show that for a fast ignition-relevant laser condition, a nickel cylinder works as a guiding material; an REB transport efficiency of 40% is obtained for a 100- μm propagation. The simulation results show that the resistive gradient guiding scheme is one of possible candidates for improving core heating efficiency.