Collective alpha particle stopping for reduction of the threshold for laser fusion using nonlinear force driven plasma blocks

Abstract

AbstractThe anomaly at laser plasma interaction at laser pulses of TW to PW power and ps duration led to a very unique generation of quasi-neutral plasma blocks by a skin layer interaction avoiding the relativistic self-focusing. This is in contrast to numerous usual experiments. The plasma blocks have ion current densities above 1011A/cm2and may be used for a fast ignition scheme with comparably low compression of the deuterium tritium (DT) fuel. The difficulty is that a very high energy flux densityE* of the ions is necessary according to the hydrodynamic theory (Bobin, 1971, 1974; Chu, 1972). This theory did not include the later discovered collective effect for the stopping power of the alpha particles. One problem is being discussed, whether the Bethe-Bloch binary collision theory or the collective collision theory of Gabor has to be applied. The inclusion of the collective effect results in a reduction of the threshold value ofE* for ignition by a factor of about fife.