A solution of the three-dimensional time-dependent Schrodinger equation, de
scribing the ionization dynamics of the hydrogen atom in a circular state i
n an electromagnetic field, is obtained by direct numerical integration. It
is shown that the observed stabilization effect can be interpreted on the
basis of the Kramers-Henneberger approach. A simple analytical model is pro
posed, which qualitatively describes the basic laws of the ionization proce
ss under the conditions of the reported calculations and laboratory experim
ents on ionization of the circular hydrogenlike 5g, m=4 state of the Ne ato
m. (C) 1999 American Institute of Physics. [S1063-7761(99)00412-6].