“…The intense pulse interaction with pre-plasma produced by the front edge may be a source of various non-linear processes, supporting the extreme characteristics of the produced ions. This is the reason for a well documented appearance of more or less significant self-focusing of intense laser beams (present in almost all of such interaction experiments), even with a possible longitudinal structure (Lei et al, 2006;La ´ska et al, 2006aLa ´ska et al, , 2006b, as well as of generation of a large number of superfast ion subgroups (La ´ska et al, 2005a(La ´ska et al, , 2005b(La ´ska et al, , 2005c. In Figure 1, up to 14 more or less pronounced peaks on the IC signals (14 ion subgroups) have been distinguished, numbered from 2 to 14, which are distributed, in principle, over three generally accepted ion groups: slow S (13,14), thermal T (12,11), and fast F (10,7).…”