The structure accretion column.

Accretion on a magnetized neutron star is considered in the case when the falling plasma is decelerated by radiation pressure above the surface and settles in a radiation-dominated accretion column. It is shown that the column has roughly triangle cross-section and the radiation from the column is captured by the freely falling plasma and reradiates to the surface of the neutron star. Therefore direct measurement of the accretion column spectrum is impossible; an observer will see radiation reflected from the surface together with the radiation of the surface which should be heated by the radiation from the column.