Electric and magnetic field generation and target heating by laser-generated fast electrons

The electric and magnetic fields generated by a beam of fast electrons in a conductor are calculated analytically, including the change in resistivity due to Ohmic heating. It is assumed that the resistivity has an arbitrary power law dependence on temperature, the fast electron current density is fixed (rigid beam), charge neutralization is instantaneous, and that magnetic diffusion is negligible. The implications for high-intensity laser-solid interactions are discussed. The minimum fast electron density for fast ignition by Ohmic heating is given, and found to be unrealistically high.