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Clumpy Flows in Protoplanetary andPlanetary Nebulae
Alexei Poludnenko, Adam Frank
University of Rochester, Laboratory for Laser Energetics
Sorin Mitran
University of North Carolina
University of Rochester Laboratory for Laser Energetics
University of Rochester Laboratory for Laser Energetics
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AstroBEAR Code and BEARCLAW packageBEARCLAW features: Unified code for computations in 1- 4 dimensions Automatic adaptive mesh refinement with flexible refinement parameters and scenarios Multi-physics capability Possibility of multiple subdomains of the computational domain with:
• different dimensionality, refinement scenarios, numerical schemes and/or Riemann solvers employed• different sets of PDEs solved on each one
A variety of output formats (AMRCLAW, TECPLOT, HDF, etc.)
AstroBEAR features: Computations in 2D, 2.5D, and 3D and access to all features without coding or recompilation Set of different Riemann solvers (full non-linear hydrodynamic, linearized Roe, linearized MHD) Generic implicit 4-th order accurate source term routine suited for arbitrary systems of source term ODEs Modular structure for user-supplied applications and a variety of provided initial conditions
Current AstroBEAR development: Full ionization dynamics and photoionization MHD Radiation driving via Sobolev approximation (e.g. radiatively driven disk outflows) MPI- and OpenMP- (SGI) based parallelization with full “knapsack-algorithm” load balancing Fast Multipole Method for elliptic equations Embedded boundaries for complicated flow geomtries
AstroBEAR results website: http://pas.rochester.edu/~wma
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CRL 618 Susan R. Trammell (UNC Charlotte) et al.
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Interacting regime of clump evolution: d = 0.95 dcrit
Non-interacting regime of clump evolution: d = 2.98 dcrit
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Qualitative characteristics of adiabatic inhomogeneous systems:
thickness of the clump system as opposed to the total clump mass clump distribution in the system as opposed to the total number of clumps
Quantitative characteristics of the adiabatic clumpy systems: Critical density, critical separation between clump centers normal to the flow:
.11
)1(32)(2
2
1
2
1
10exp0
stc
SC
CCCDCCCDcrit
FF
t
ttattvad
Clump destruction length LCD, distance traveled by a clump prior to its breakup
Those two parameters allow one to distinguish between interacting andnoninteracting regimes of clump system evolution
Poludnenko, A.Y., Frank, A., Blackman, E.G. 2002, ApJ, 576, 832
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Radiative Hypersonic Cosmic Bullets
An example of a radiatively cooled inhomogeneous environment
Systems are practically always in the noninteracting regime, i.e. there is no lateral expansion and merging
The main process is clump fragmentation via instabilities
The properties of the global flow determine the initial spectrum of fragments that are formed
The details of clump distribution determine the final spectrum of fragments
The final spectrum of fragments determines the structure and properties of the resulting system
Mach 20 radiatively cooled bullet, ambient density 102 cc-1, clump density 104, tcool/thydro = 2.8*10-3
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Mach 10 radiatively cooled bullet, ambient density 103 cc-1, clump density 105, tcool/thydro = 2.5*10-2
Mach 10 radiatively cooled bullet, ambient density 102 cc-1, clump density 104 cc-1, tcool/thydro = 0.25
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Mach 20 radiatively cooled bullet, ambient density 103 cc-1, clump density 105, t = 204 yrs. , tcool/thydro = 2.8*10-5
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Mach 200 radiatively cooled bullet, ambient density 102 cc-1, clump density 104, t = 18.3 yrs. , tcool/thydro = 3.7
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