Rashed, H. Y. 1996,
Cyclotron Luminosity of Offset Accretion Shocks Onto Magnetic White Dwarfs,

Mu'tah Journal for research and studies, Vol. 11 No. 4, 11.

Abstract:
The compact white dwarf x-ray binary AM-Her(culis) objects differ from the mass transfer white dwarf binary systems by containing a strongly magnetic white dwarf, B_* = 10-60 MG.  The AM-Her systems being relatively faint are not easily modeled.  Thus the discovery of rapid, 1-3 s, optical quasi-periodic oscillations (QPOs) in some of the AM-Her systems is quite interesting (Middleditch 1982).  Middleditch suggested that QPOs are due to an instability of radiative shock waves discovered by Langer Chanmugam and Shaviv (1981) during time-dependent calculations of the accretion flows onto magnetic white dwarfs.  If this is correct, then the QPOs can be used to study the radiating plasmas under conditions similar to those found in terrestrial magnetically confined fusion devices.  Also they serve to place constraints on the properties of the AH-Her systems (eg. See Wood, Imamura, and Wolff 1993).  The QPOs are observed in the optical emission, thus, they are thought to be due to cyclotron emission from the radiating strongly magnetic shocked plasma.  In this work, the effect of funnel's extension on the QPOs is studied.