Corrugation Instability of a Slow Shock Wave and Variability of Low-Mass X-Ray Binaries
Session 52 -- Interacting Binaries: Accretion Phenomena
Display presentation, Thursday, January 13, 9:30-6:45, Salons I/II Room (Crystal Gateway)

## [52.04] Corrugation Instability of a Slow Shock Wave and Variability of Low-Mass X-Ray Binaries

M. Edelman (NYU)

It is shown that isothermal and adiabatic oblique strong slow shock waves are aperiodically unstable. In the case of the accretion radiative shock waves, the disturbances with wavelength $\lambda \geq l_{c}M_{A}$ ( $l_{c}$ - cooling length, $M_{A}$ - Alfven Mach number ) are subjected to an oscillatory instability; waves with $\lambda < l_{c}M_{A}^{2}$ are aperiodically unstable.

In the strong magnetic field of AM Her systems, the shock wave formed at the base of the accretion column at the surface of the white dwarf is slow. Its corrugation instability can lead to the quasiperiodic oscillations and the noise which are observed in the power spectra of the "polars" AN UMa and E1405-451 on the frequencies f $\sim$ 1 Hz. Observation of the high-frequency noise ( f $\sim 10^{3} - 10^{5}$ Hz ) connecting with the variability on the frequencies f $\sim$ 1 Hz could confirm the validity of the suggested hypothesis.