  Two-dimensional simulations of ion beam driven fast ignition are presented.
Ignition energies of protons with Maxwellian spectrum and carbon ions with
quasimonoenergetic and Maxwellian energy distributions are evaluated. The
effect of the coronal plasma surrounding the compressed deuterium-tritium is
studied for three different fuel density distributions. It is found that quasi-
monoenergetic ions have better coupling with the compressed deuterium-tritium
and substantially lower ignition energies. Comparison of quasimonoenergetic
carbon ions and relativistic electrons as ignitor beams shows similar laser
energy requirements, provided that a laser to quasimonoenergetic carbon ion
conversion efficiency around 10% can be achieved.
