Beam plasma interactions in HIF

A review is presented of some recent studies on the effects of beam characteristics (energy, beam spot size, radial particle distribution, charge state) on the predicted performance of directly driven HIF targets. Phenomena of particular importance in such beam-plasma interaction are (i) the effects of plasma density and temperature on ion range, and (ii) the effects of charge exchange and accretion due to the beam-target interaction. Range effects are shown to be important for energy-coupling, Rayleigh-Taylor instability and fission fragmentation effects. Effects associated with the charge state of the incident ion beam are shown to lead to a reduction in target energy input, beam coupling efficiency and fusion yield, thus demanding some degree of charge neutralization