Shocks and jets from the laboratory environment to the astrophysical regime: Transforming AstroBEAR into an all purpose MHD simulation package.

摘要

Supersonic jets and shocks play an important role in numerous astrophysical phenomena, ranging from stellar formation to active galactic nebulae (AGN). Laboratory astrophysics opens up new avenues for research into these jets and shocks, and computer simulations show great promise in linking laboratory and astronomical data. To date, the most effective codes for the laboratory environment are not readily available and lack magnetic fields, a key component in astrophysical jets and future magnetized laboratory experiments. Also no 3D simulation code has had its non-local thermodynamic equilibrium (LTE) cooling, essential for generating emission maps for comparison with astronomical observations, rigorously tested against an accepted baseline. The focus of this dissertation research was to improve an existing magneto-hydrodynamic code, AstroBEAR, to better model jets and shocks in laboratory and astrophysical environments, with the ultimate goal of developing a code that can link astronomical and laboratory data.;The work outlined in this dissertation facilitates the connection between astronomical and laboratory data in two areas. First, we added a multiple material and non-ideal equation of state capability into AstroBEAR to handle the high density ionized plasmas that characterize laboratory astrophysics experiments and now have the first working 3D MHD code capable of simulating the laboratory environment. We used AstroBEAR in 2.5 D hydrodynamic mode to simulate a series of experiments carried out on the OMEGA laser, and compared the simulations with experimental data.;Secondly, we improved AstroBEAR's handling of radiative cooling, specifically in the post-shock cooling zones prevalent in many astrophysical jets. The first ever validation tests of a 3D code against a fully non-LTE 1D radiative cooling atomic code show explicitly that AstroBEAR correctly models post-shock radiative cooling down to the resolution and micro-physics limits. We used this improved cooling to simulate the HH 110 jet and conclude from these simulations that any model of stellar jet formation must be able to produce processing and pulsing outflow. Overall the improvements of AstroBEAR's ability to handle jets and shocks in the laboratory and astrophysical environments position it to potentially link observational data with magnetized laboratory experiments.