AstroBEAR: Astrophysical Fluid and Magnetofluid Dynamics with BEARCLAW

1. University of Rochester Laboratory for Laser Energetics AstroBEAR:Astrophysical Fluid and Magnetofluid Dynamicswith BEARCLAW Alexei Poludnenko University of Rochester Computational Astrophysics Group Leader: Adam Frank Postdoctoral fellow: Peggy Varniere Graduate Student: Andrew Cunningham University of Rochester, Laboratory for Laser Energetics Support from: NSF, NASA, DOE/NNSA BEARCLAW: Sorin Mitran University of North Carolina

2. AstroBEAR: Application Driven Code Our interests center around outflows and accretion in the context of stellar evolution: • Young stellar object jets and molecular outflows • Planetary nebulae and circumstellar outflows • Accretion disks and planet formation • Magneto-centrifugal winds and accretion disk structure • as well as … • Mass outflows in active galactic nuclei • Laboratory Astrophysics: theoretical modeling and code verification HH 47 Patrick Hartigan (Rice University)

3. AstroBEAR features • Computations in 2D, 2.5D, and 3D • access to all features without coding or recompilation • Set of different Riemann solvers: • full non-linear hydrodynamic • linearized Roe • linearized (arithmetic average) MHD • Generic implicit 4-th order accurate source term routine • suited for arbitrary systems of source term ODEs • Modular structure for user-supplied applications • Variety of provided initial conditions • shocks and blast waves (tabulated and defined through Mach number) • arbitrary density distributions: user-specified and random • disk wind outflows with user-specified properties • jets • accretion disks

4. AstroBEAR features • Built-in physics modules: • radiative cooling via cooling curve • radiation driving via Thomson scattering • central gravity • Current AstroBEAR development: • Full ionization dynamics and photoionization • MHD • Radiation driving via Sobolev approximation (e.g. radiatively driven disk outflows) • Current BEARCLAW development: • MPI – and OpenMP – based parallelization with full load balancing • Fast Multipole Method for elliptic equations • Embedded boundaries for complicated flow geomtries BEARCLAW website: http://www.amath.unc.edu/Faculty/mitran/bearclaw.html AstroBEAR results website:http://pas.rochester.edu/~wma

5. Radiative hypersonic cosmic bullets HH 47 Bowshock Patrick Hartigan (Rice University) CRL 618 Susan R. Trammell (UNC Charlotte) et al.

6. Radiative Hypersonic Cosmic Bullets: Computational Challenges • Such systems are very susceptible to: • strong oscillations in density and pressure resulting in unphysical solutions • formation of carbuncles and other similar features • formation of “near-vacuum” cavities • “run-away” cooling • That required: • fully nonlinear Riemann solver • accurate treatment of transverse wave propagation for dimensional coupling • high-order accurate source term integration method for very stiff systems of ODEs

7. Mach 10 radiatively cooled bullet ambient density 103 cc-1, clump density 105 cc-1, tcool/thydro = 2.5*10-2 AMR grid generation in the system Synthetic observation (shown is the logarithm of the total projected emissivity)

8. Extremely strongly cooled systems Mach 20 radiatively cooled bullet, ambient density 102 cc-1, clump density 104 cc-1, tcool/thydro = 2.8*10-3 Mach 20 radiatively cooled bullet, ambient density 103 cc-1, clump density 105 cc-1, tcool/thydro = 2.8*10-5

9. Laboratory Astrophysics Observation – Simulation – Experiment … • Excellent testbed for : • code verification • verification of analytical models • development of experimental techniques Paul Drake et al., University of Michigan

10. Shock - Clumpy Cloud Interaction (Poludnenko et al. 2004) Experimental Study In collaboration with Paul Drake et al., University of Michigan

11. Shock - Clumpy Cloud Interaction 2D Numerical Study • System of 200 clumps • Density contrast  = 40 • Clump radius 25 m • Domain size 3 x 4 mm • Resolution: • 3264  2720 at the • finest refinement level

12. Supersonic Jet-Wind Interaction (Lebedev 2001, 2004) Experimental Study • Development of experimental design and diagnostic techniques for z-pinch devices • Jet formation by means of supersonic convergent conical flows (Canto etal. 1988) • Jet interaction with supersonic cross-wind (Canto & Raga 1995) • An example of a hypersonic radiatively cooled system • Test-bed for 3D code verification

13. Supersonic Jet-Wind Interaction 3D Numerical Study • Radiatively cooled system • Mach 20 jet interacting with a Mach 6 cross-wind • Domain resolution at the finest level 384 128  64 • Temperature: jet – 1.1 104 K, wind – 1.1 104 K, ambient – 9.9 104 K • Density: jet– 751 cc-1, wind – 300 cc-1, ambient– 90 cc-1

14. 1D test: shock tube problem 2D test: Orzag-Tang vortex MHD in AstroBEAR Please, see poster by Peggy Varnière et al. • Integration is performed with the help of the linearized Riemann solver (J. Rossmanith) • Divergence cleaning is implemented via the gradient of a function –, where  is the solution of the Poisson equation

16. Dependence of shock propagation velocity on density distribution • Shock front velocity: • uniform density – 57.1 km/s • clumpy system – 51.95 km/s • average density – 44.94 km/s • Velocity difference between the • last two cases: > 15% A.Y. Poludnenko, K.K. Dannenberg, R.P. Drake, A. Frank, J. Knauer, D.D. Meyerhofer, M. Furnish, J. Asay, 2003, astro-ph/0305146

17. Contents • Why AstroBEAR – applications • BEARCLAW package and AstroBEAR • Adiabatic inhomogeneous systems: analytical and numerical modeling • Experimental study and code verification: Laboratory Astrophysics • Radiatively cooled cosmic bullets

18. Summary • Development of the experimental technique for the study of hydrodynamics of • inhomogeneous media • Theoretical model verification • Code verification