The mechanisms of heating of the electronic component of large deuterium cl
usters by a superatomic ultra-short laser pulse field are considered. Durin
g pulse rise, the so-called "vacuum heating" plays the determining role. El
ectrons escaping from a cluster into the vacuum with a low energy return ba
ck in a time equal to the period of the laser under laser field action. The
returning electrons have a higher energy (on the order of the vibrational
energy in the laser radiation field), which causes cluster heating. As the
laser field increases, the electronic temperature largely grows at the expe
nse of decreasing the Coulomb potential energy of electron repulsion becaus
e of a decrease in the number of electrons. The dynamics of above-barrier c
luster ionization at the leading edge of a superatomic laser pulse is calcu
lated. The results are discussed in the light of recent experiments aimed a
t creating desktop sources of monoenergetic neutrons formed as a result of
the fusion of deuterium nuclei in a cluster plasma. (C) 2001 MAIK "Nauka/ I
nterperiodica".