Proton Beam Fast Ignition Fusion: Synergy of Weibel and Rayleigh-Taylor Instabilities

The proton beam generation and focusing in fast ignition\footnote{ M. Roth et al , Phys. Rev. Lett. 86, 436 (2001); M. Tabak et al, Phys. Plasmas 1 (5), 1626 (1994). } inertial confinement fusion\footnote{ K. .A. Brueckner and V. Stefan, \textit{Possibility of Anomalous Plasma Effects in~Heavy-Ion Beam Fusion},~Bul. Am. Phys. Soc., 27, 8 (1982).} is studied. The spatial and energy spread of the proton beam generated in a laser-solid interaction is increased due to the synergy of Weibel and Rayleigh-Taylor instabilities.\footnote{ V. Alexander Stefan, \textit{Nonlinear Electromagnetic Radiation Plasma Interactions}, (S-U-Press, 2008)} The focal spot radius can reach 100$\mu $m, which is nearly an order of magnitude larger than the optimal value. The energy spread decreases the beam deposition energy in the focal spot. Under these conditions, ignition of a precompressed DT fuel is achieved with the beam powers much higher than the values presently in consideration.