Conical microducts and minithrottles can be used to accelerate micrope
llets of fusionable fuel up to very high speeds (similar to 10(8) cm/s
). The central collision of two pellets flying in opposite directions
can produce a hot plasma where fusion reactions are triggered. The mai
n drawback of this scheme is the short confinement time provided by th
e external guide tube (throttle). To obtain high yield, an extra force
of confinement is advisable. In this paper, the performance of fuel i
mplosions within conical targets and the effect of ultrashort magnetic
fields and pinch forces are analyzed. Although very high currents are
needed to stretch the confinement time, modern technologies based on
pulse-power machines and fast discharges induced by ultrashort lasers
can provide a solution to this problem.