Type I X-ray bursts and superbursts on neutron stars release sudden and intense radiation fields into their surroundings .
Here , we consider the possible effects of these powerful explosions on the structure of the accretion disk .
The goal is to account for the apparent evolution of the innermost regions of the accretion disk around 4U 1820–30 during a superburst .
Three different processes are considered in detail : radiatively or thermally driven outflows , inflow due to Poynting-Robertson drag , and a structural change to the disk by X-ray heating .
Radiatively driven winds with large column densities can be launched from the inner disk , but only for L / L _ { \mathrm { Edd } } \gtrsim 1 , which is expected to be obtained only at the onset of the burst .
Furthermore , the predicted mass outflow rate is less than the accretion rate in 4U 1820–30 .
Estimates of the Poynting-Robertson or radiative drag timescale shows that it is a very efficient means of removing angular momentum from the gas .
However , the analytical results are likely only applicable at the innermost edge of the disk .
X-ray heating gives a change in the disk scale height that is correlated with the blackbody temperature , as seen in the evolution during the 4U 1820–30 superburst .
If this change in the scale height can alter the surface density , then the viscous time ( with \alpha \sim 0.03 – 0.2 ) is the closest match to the 4U 1820–30 results .
We expect , however , that all three processes are likely ongoing when an accretion disk is subject to a sudden heating event .
Ultimately , a numerical simulation of a disk around a bursting neutron star is required to determine the exact response of the disk .
Magnetic truncation of the accretion flow is also considered and applied to the 4U 1820–30 X-ray reflection results .