  We present the results of the detailed experimental study of multiple
ionization of Ne and Ar by 25 and 7 fs laser pulses. For Ne the highly
correlated "instantaneous" emission of up to four electrons is triggered by a
recollisional electron impact, whereas in multiple ionization of Ar different
mechanisms, involving field ionization steps and recollision-induced
excitations, play a major role. Using few-cycle pulses we are able to suppress
those processes that occur on time scales longer than one laser cycle.
