S. C. Tripathy
Articles written in Journal of Astrophysics and Astronomy
Volume 10 Issue 1 March 1989 pp 21-34
Starting from a set of general equations governing the dynamics of a magneto-fluid around a compact object on curved space time, a fairly simple analytical solution for a test disc having only azimuthal component of velocity has been obtained. The electromagnetic field associated has a modified dipole configuration which admits a reasonable pressure profile for the case of fully relativistic treatment of Keplerian type of velocity distribution
Volume 11 Issue 4 December 1990 pp 461-474
In this paper we discuss the equilibrium configuration of a plasma disc of infinite conductivity around a slowly rotating compact object, and obtain the pressure profiles, and the structure of magnetic field lines for co and counter-rotating discs.
Volume 14 Issue 2 June 1993 pp 103-114
In this paper, the analytical and numerical results of the stability analysis of the accretion disk at the inner boundary is presented. Including the effect of finite conductivity in the disk dynamics, a simple calculation considering only the radial perturbation has been carried out. Within local approximation, it is concluded that the disk is stable to Kelvin-Helmholtz and resistive electromagnetic modes whereas the magnetosonic mode can destabilise the disk structure.
Volume 14 Issue 3-4 December 1993 pp 167-179
A two-dimensional instability analysis for a magneto-keplerian disk flow around a compact object is presented here. Using the eigenvalue technique, linearly coupled perturbed equations have been numerically solved within the local approximation. It is concluded that Kelvin-Helmholtz, magnetosonic (fast and slow) and resistive electromagnetic modes exist. However, only the magnetosonic mode can destabilise the disk structure. Further, we discuss the properties of different modes as a function of disk parameters and plot the eigenmode structures for different physical quantities.
Volume 21 Issue 3-4 September 2000 pp 349-352
Using the GONG data for a period over four years, we have studied the variation of frequencies and splitting coefficients with solar cycle. Frequencies and even-order coefficients are found to change significantly with rising phase of the solar cycle. We also find temporal variations in the rotation rate near the solar surface.
Volume 21 Issue 3-4 September 2000 pp 357-360
Using intermediate degree
Volume 29 Issue 1-2 March 2008 pp 207-210
We apply the ring diagram technique to source regions of halo coronal mass ejections (CMEs) to study changes in acoustic mode parameters before, during, and after the onset of CMEs.We find that CME regions associated with a low value of magnetic flux have line widths smaller than the quiet regions, implying a longer life-time for the oscillation modes. We suggest that this criterion may be used to forecast the active regions which may trigger CMEs.
Volume 40 | Issue 5
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