Diagnostics of disk-magnetosphere interaction in neutron star binaries

The interaction between the magnetospheres of accreting neutron stars and accretion disks plays at key role in determining the properties of many accretion-powered neutron star X-ray sources and the recycled binary and millisecond rotation-powered pulsars. Here we show that the behavior of the horizontal branch quasi-periodic intensity oscillations in low mass X-ray binaries and the correlation between the magnetic fields and periods of binary and millisecond pulsars are sensitive probes of the state of the inner disk.