  The small sub-barrier tunneling probability of nuclear processes can be
dramatically enhanced by collision with incident charged particles.
Semiclassical methods of theory of complex trajectories have been applied to
nuclear tunneling, and conditions for the effects have been obtained. We
demonstrate the enhancement of alpha particle decay by incident proton with
energy of about 0.25 MeV. We show that the general features of this process are
common for other sub-barrier nuclear processes and can be applied to nuclear
fission.
