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Center for Nonlinear Studies |
Stars are formed in Molecular Clouds (MCs), which are lightly ionized and at large scales obey nearly ideal magnetohydrodynamics. Magnetic structure inherited from large scales influence the dynamics of the dense ISM, and can provide support against gravitational collapse that can slow or even halt star formation; however, the magnetic field is observationally difficult to measure. Polarized far IR/sub-mm dust emission – which arises due to alignment of dust grains with the local magnetic field – has emerged as a key tool to study magnetic fields in these regions. I will present my work on linking magnetohydrodynamics simulations (which provide a complete 3D picture of a toy model MC) to submillimeter observations of MCs using synthetic polarimetric techniques. I will also present my work with the Planetary Defense group at LLNL. Catastrophic impact events might be avoided by employing nuclear explosives as a means to disrupt or deflect an incoming asteroid. A semi-analytic energy deposition scheme for soft x-rays in rocky material is used to initialize these scenarios, which are modeled using the Adaptive Smoothed-Particle Hydrodynamics (ASPH) code Spheral++: a code that implements material strength and damage for realistic fragmentation. Using gravitational N-body techniques, I will also present preliminary results on the evolution of fragment orbits following disruption to assess the effectiveness and risks associated with this planetary defense strategy.
Host: Wesley Even