Fast ignition of precompressed DT fuel placed in an absolutely rigid heat-insulated cylinder

A two-dimensional axisymmetric problem on fast ignition of a cylindrical target of precompressed DT-mixture surrounded by a stationary heat-insulated shell is considered. The target end is ignited with a proton beam, the intensity of which is independent of the radial coordinate. Self-radiation of plasma and alpha-particles of the thermonuclear reaction freely escape out of the fuel through the lateral boundary of the shell. It is shown that the ignition energy threshold for the mixture density 22 and 110 g/cm(3) about 10 times less than in the case of the known problem with the radius of the beam much less than the radius of fuel. Previously developed quasi-one-dimensional model underestimates the ignition energy threshold by the target radius about 4 times in comparison with the problem under consideration. Estimates for the magnetic field and the shell density at which the corresponding problems are in some sense close to the problem under consideration are presented.