117 citations · 279 across the 10 of their papers we have counts for
7 papers · 1 filter
Oscillations of tori in the pseudo-Newtonian potential
Eva Sramkova, Ulf Torkelsson, Marek A. Abramowicz
Context. The high-frequency quasi-periodic oscillations (HF QPOs) in neutron star and stellar-mass black hole X-ray binaries may be the result of a resonance between the radial and…
Epicyclic Oscillations of Fluid Bodies: Newtonian Nonslender Torus
Omer M. Blaes, Eva Sramkova, Marek A. Abramowicz +2
We study epicyclic oscillations of fluid tori around black holes (in the Paczynski-Wiita potential) and derive exact analytic expressions for their radial and vertical eigenfrequen…
Propagation of non-linear circularly polarised Alfven waves in a homogeneous medium
Rim Turkmani, Ulf Torkelsson
We study the evolution of non-linear circularly polarised Alfven waves by solving numerically the time-dependent equations of magnetohydrodynamics (MHD) in one dimension. We examin…
Dissipation of non-linear circularly polarized Alfven waves
R. Turkmani, U. Torkelsson
We study propagating Alfven waves by solving the time-dependent equations of magnetohydrodynamics (MHD) in one dimension numerically. In a homogeneous medium the circularly polariz…
The response of a turbulent accretion disc to an imposed epicyclic shearing motion
Ulf Torkelsson, Gordon I. Ogilvie, Axel Brandenburg +3
We excite an epicyclic motion, whose amplitude depends on the vertical position, , in a simulation of a turbulent accretion disc. An epicyclic motion of this kind may be caused…
Magnetic torques between accretion discs and stars
Ulf Torkelsson
I show in this paper that two types of magnetic torques can appear in the interaction between an accretion disc and a magnetic accretor. There is the well-known torque resulting fr…