Conclusions

We have considered a perturbation analysis of accretion shocks with a composite cooling function, in which there is a bremsstrahlung cooling term and a power-law term mimicking the effects of optically thick cyclotron cooling. We have found that in the limit of zero cyclotron cooling the first harmonic of the shock oscillation is stable while the higher harmonics are unstable. For the case with moderately strong cyclotron cooling (), the first two harmonics are stable but the higher harmonics are unstable. For very strong cyclotron cooling (), the first eight harmonics we have obtained are stable. The presence of cyclotron cooling therefore stablises the shock oscillations.

© Copyright Astronomical Society of Australia 1997