Time-dependent compression of cylindrical or spherical ideal gas volumes

Two problems of time-dependent compression of ideal (inviscid and not heat-conducting) gas, related with the idea of controlled inertial thermonuclear fusion (CITF) are considered. In first of them for time, close to time of an acoustic wave run by an initial cylindrical or spherical volume, the gas is isentropically compressed from rest to rest. Such energy optimal compressing does not ensure, however, the required level of temperature. In opposite to it when faster compressing with "a head shock" (HS) the necessary density is not reached. In the second problem the centered compressing wave of characteristics coming to an axis or to center of symmetry (further-CS) simultaneously with HS is introduced. As a result it is possible to create the conditions required for CITF.