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Simple Model Of  Accretion  Onto  Isolated  Neutron   Star  With
                      Synchrotron Cooling
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{\bf Abstract.}

 In this work we modeled accretion  onto  the  isolated
neutron star (INS) from the interstellar medium in the  case  of
spherical symmetry for different values of  the  magnetic  field
strength, ambient gas density and NS's mass. We  try  to  verify
the idea that if the radius of corotation, $R_{co}$,
is less than the Alfven radius, $R_A$ ,
the shell will form around  the  INS  and   $R_A$
will decrease to $R_{co}$   and the periodic X-ray source  will  appear
(see M.Colpi et al., 1993   A\&A  269,   319,   hereafter  CTL).
Dependence of  $R_A$  from $t$ in our model coincides  well  with  the
analytic formula from CTL. The  periodic  sources  with  $P$  from
several minutes to several months can appear.
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