  Inertical Confinement Fusion configuration model is analized for direct
ignition without an ablator. The compression of the target pellet is neglected
and rapid volume ignition is achieved by a laser pulse, which is as short as
the penetraton time of the light across the pellet. The reflectivity of the
target is assumed to be negligible, and the absorptivity is constant so that
the light pulse can reach the opposite side of the pellet. The necessary pulse
length and pulse strength is calculated.
