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MHD Simulations
It is all about nice colors...Model Star:
Miscellaneous Research
This is a collection of my past and current research topics that are not directly related to massive star winds. Many of the calculations below were done using IBM Supercomputers SP3 owned by national labs, like Oak Ridge. Visualizations were done using Tecplot or Ensight. Feel free to use any of the images or animations in your presentations. This page is being updated continually...
Terascale Supernova Initiative
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The Terascale Supernova Initiative (TSI) is a multidisciplinary collaboration of a number of institutions including a national lab and several universities. Click the above link to view the official site of TSI. The aim of TSI is to develop models for core collapse supernovae and enabling technologies in radiation transport, radiation hydrodynamics, nuclear structure, linear systems and eigenvalue solution, and collaborative visualization. TSI is sponsored by the Department of Energy's Office of Science Scientific
Discovery Through Advanced Computing (SciDAC) program. My role was to examine the role of magnetic fields in core collapse supernovae models. I used to work with Prof. John Blondin at NCState Department of Physics. |
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Non-Linear Thin-Shell Instability (NTSI) in Magnetized Cold Slabs:I found that weak magnetic fields have very little effect on the growth of NTSI, but moderately strong fields within dense slabs can substantially influence both the growth and the structure of the NTSI. Moreover, the presence of a strong magnetic field leads to an asymmetric NTSI growth wherein some wave modes are suppressed along the direction of the field but not other directions. |
Here is an AVI movie of the time evolution
of a model with fairly high rotation rate.An AVI movie of the time evolution of a model with moderate rotation rate and an initial uniform B field. |
Magneto-Rotational Instability (MRI) in Standing Accretion Shocks (SAS):I run numerical magnetohydrodynamic (MHD) simulations of the effect of weak magnetic field on idealized Standing Accretion Shocks (SAS) that arise in classical core-collapse supernovae, wherein an expanding shock front stalls at a radius $\sim$ 100-200 km and remains quite stationary for a relatively long period of time $\sim$ 300 ms. In those models specific angular momentum is fixed at the outer boundary. To ensure that the initial seed magnetic field has a poloidal component, a necessary condition for the possible growth of magneto-rotational instability (MRI), we use a weak dipole magnetic field. Our fully dynamical simulations of this interaction of rotation and the magnetic field in SAS in the context of core-collapse supernovae, show a substantial exponential growth of the magnetic field energy that can exceed 8 order of magnitude, and which dominates the linear growth process of ``field-line wrapping''. This is characteristic of MRI growth in our models. |
Neutrino-Driven Pro-Neutron Star Wind
Coming soon...