The radial–azimuthal instability of a hot two-temperature accretion disc with advection |
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| Authors: | Ding Shi-Xue Yang Lan-Tian Wu Xue-Bing Lu Ye |
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| Institution: | Department of Physics and Institute of Astrophysics, Huazhong Normal University, Wuhan 430079, China;Department of Physics, Xiang Fan College, Xiang Fan 441053, China;Beijing Astronomical Observatory, Chinese Academy of Sciences, Beijing 100080, China |
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| Abstract: | The radial–azimuthal instability of a hot two-temperature accretion disc with advection is examined in this paper. We find that the inclusion of very little advection has significant effects on two acoustic modes for a geometrically thin, cooling-dominated two-temperature disc, but has no effect on acoustic modes for a geometrically slim, cooling-dominated two-temperature disc. We also find that, when azimuthal perturbations are considered, the stability properties of the disc are different from those in the pure radial perturbation case. An increase of the azimuthal wavenumber will stabilize the acoustic modes but make the viscous and thermal modes more unstable for a geometrically thin, cooling-dominated two-temperature disc. It makes the thermal mode more unstable and the acoustic mode more stable, but only affects the instability of the viscous mode for short-wavelength perturbations for a geometrically slim, cooling-dominated two-temperature disc. For a geometrically slim, advection-dominated two-temperature disc, the increase of the azimuthal perturbation makes the I- and O-modes more stable and the thermal mode more unstable, but has no effect on the viscous mode. |
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| Keywords: | accretion accretion discs instabilities |
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