We have investigated the influence of X-ray irradiation on the vertical structure of the outer accretion disk in low-mass X-ray binaries by performing a self-consistent calculation of the vertical structure and X-ray radiation transfer in the disk .
Penetrating deep into the disk , the field of scattered X-ray photons with energy E \gtrsim 10 keV exerts a significant influence on the vertical structure of the accretion disk at a distance R \gtrsim 10 ^ { 10 } cm from the neutron star .
At a distance R \sim 10 ^ { 11 } cm , where the total surface density in the disk reaches \Sigma _ { 0 } \sim 20 g cm ^ { -2 } , X-ray heating affects all layers of an optically thick disk .
The X-ray heating effect is enhanced significantly in the presence of an extended atmospheric layer with a temperature T _ { atm } \sim ( 2 \div 3 ) \times 10 ^ { 6 } K above the accretion disk .
We have derived simple analytic formulas for the disk heating by scattered X-ray photons using an approximate solution of the transfer equation by the Sobolev method .
This approximation has a \gtrsim 10 % accuracy in the range of X-ray photon energies E < 20 keV .

DOI : 10.1134/S1063773711050045