>Hydrodynamic expansion of the solar corona is the basis for solar corpuscular radiation. The quiet day coronal temperatures of 1 to 2 x 10/sup 6/ deg K yield a solar wind of several hundred km/sec and a density of 5 to 50 particles/cm/sup 3/ at the orbit of Earth. The solar wind draws out into space the lines of force of the general one-gauss solar field, to give an interplanetary field that is basically spiral in character with a density of the order of a few times 10/sup -5/ gauss at the orbit of Earth. The enhanced corona may sometimes have temperatures of 4 x 10/sup 6/ deg K or more immediately following a large flare. Such explosive heating leads to a 1 to 2 x 10/sup 3/ km/ sec blast wave into planetary space. The blast wave sweeps up the quiet-day solar wind ahead and kinks the quiet-day field, raising the density of the field to several times 10/sup -4/ gauss on some occasions. The galactic cosmic ray particles are swept back by the kink, producing a Forbush-type intensity decrease. Altogether, the blast wave and its magnetic field constitute the enhanced solar corpuscular radiation. It is shown that themore » alternative magnetic tongue model of Gold and others STA1960! is untenable because the tongue would not reach the earth until many hours after the arrival of the blast wave. (auth)« less