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Exploring Astrophysical Clumps, Jets, and Bubbles: Laboratory and Numerical Insights

This study delves into the dynamics of astrophysical clumps, jets, and bubbles, focusing on environments such as planetary nebulae and young stellar objects (YSOs). The research combines observational data with laboratory experiments performed using high-energy density devices. It explores complex hydrodynamic and magnetohydrodynamic systems, analyzing mass loss in stellar environments and the effects of turbulence, shock propagation, and clumpy flows. The findings contribute to our understanding of astrophysical phenomena and aim to bridge observational science with experimental astrophysics.

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Exploring Astrophysical Clumps, Jets, and Bubbles: Laboratory and Numerical Insights

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  1. Clumps, Jets and BubblesAdventures on the SKY,In a BOX (computer),And in the LAB Adam Frank (UR, LLE) A. Poludnenko, T. Gardiner, A Cunningham E. Blackman (UR), S Lebedev (IC), P. Drake (UM)

  2. Clumps, Jets and BubblesThe Dyson Era • Stellar Mass Loss Systems • YSOs, Planetary Nebula,WR Bubbles, LBV, SNe • Observations • Wind blown BUBBLES. • Collimation (JETS) and Pulsing. • Heterogeneous plasma systems (CLUMPY FLOWS)

  3. Clumps, Jets and Bubbles • Astrophysics • Complex hydro/MHD systems • Non-linear, time dependent behaviors • Tools • Analysis • Numerical Simulation • Direct laboratory experiments!

  4. UR/LLE Omega Laser The New Laboratory Astrophysics • Astronomy has been observational science. • Astro environments = extremes of known physics. • High Energy Density (HED) Devices = Fusion Lasers, etc Create macroscopic volumes of HED plasmas Hydro/MHD Equations have scale-invariant solutions. SIMILARITY!

  5. … and at larger scales: • Mass outflows from AGN’s Application # 1 Clumpy Flows • Flows in inhomogeneous (clumpy) media are common • May be affected by mass-loading processes • Mixing, turbulence, shock propagation • Planetary Nebulae (e.g. NGC 7293, NGC 2392) • Wolf-Rayet nebulae (e.g. RCW 58) • Supernova remnants (e.g. Cygnus Loop) • Regions of low-mass star formation (e.g. Trapezium cluster, HH regions) • Molecular clouds

  6. The Physics of Clumpy Flows (in a box) Poludnenko, Frank & Blackman 2002 AMRCLAW based adaptive mesh refinement Mach 10.0 shock wave interacting with a system of 3 identical clouds, density contrast 500.0, adiabatic regime, shown is logarithmic density

  7. The Physics of Clumpy Flows (in a box) Poludnenko, Frank & Blackman 2002 Mach 10.0 shock wave interacting with a system of 14 identical clouds, density contrast 500.0, adiabatic regime, shown is logarithmic density

  8. Clumpy Flows: Characterizing the System Kinetic Energy Mixing Note: Do not see mass loading! Clumps disperse first (cooling? Mellema et al 2002)

  9. Critical density, critical separation between clump centers normal to the flow: Clumpy Flows: Characterizing the System What Matters? • 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 clumpy systems: • Clump destruction length LCD, distance traveled by a clump prior to its breakup These two parameters distinguish between interacting and noninteracting regimes of clump system evolution

  10. Application # 1 Clumpy Flows (in the lab)Poludnenko et al 2002 Clumpy Cloud experiment design for HEDLA • Realistic clump volume fraction • “OK” clump/ambient medium density ratio (40) • Reasonably steady shock • Strong enough shock convert clumps to plasma

  11. Strongly Interacting Regeme •  y = 10 m  10 % dcrit •  x = 5.32 m  6 % LCD Simulating the Experiment (Large N system) • Mach 10 steady shock • System of 200 clumps • Density contrast  = 40 • Clump radius 25 m • Domain size 3 x 4 mm

  12. Application # 2 Astrophysical Jets • Appear in an ever widening array of environments: • AGN • YSOs • PNe • Unresolved issues: • Collimation (MHD fast rotators) • Propagation (variability, knots, stability) • Connection to wider bubbles (Gardiner et al 2002)

  13. Application # 2 Astrophysical Jets • Unresolved issues: • Interaction and the generation of turbulence • (Cunningham et al 2002)

  14. The Issue of Converging Conical Flows. Canto et al 1988 Frank Balick Livio 1996 Application # 2 Astrophysical Jets (in the lab)Lebedev et al 2002

  15. Application # 2 Astrophysical Jets (in the lab)Lebedev et al 2001 Z-Pinch Laboratory Jets • 16 wire Z-pinch: • MAGPIE Imperial College • “Precursor” plasma flows off wires. • Canto-esque conical converging flow

  16. Test Canto Jet Formation Model Vz = 200 km/s M > 15 Vz = 200 km/s M > 15 Low Z = low radiative cooling = poor collimation

  17. Future: Test Jet/ISM interactions • Opportunity to test • a variety of astrophysical • jet issues • Collimation • Propagation • Stability • MHD (?) • Pulsing (?)

  18. Jet Deflection via Side-Wind Interactions

  19. Conclusions: Future Directions • Clumpy Flows • Strong Cooling (Mellema et al.) • Mass Loading (How much? How fast?) • Global Configurations (3-D models) • Jets • MHD and Wide Angle Winds • Jet interactions driving turbulence • Laboratory Astrophysics • The hard but exciting work has just begun. • “Spirited Invention” • Bubbles • Magnetized Wind Bubble Model incorrect initial conds. • PNe = winds from strongly magnetized rotators.

  20. The Promise of HEDLANew Tools = New Science? • Astronomy has been observational science • few experiments possible (chemistry/dust) • Astro environments = extremes of known physics. • What does HIGH ENERGY DENSITY really mean. • HEDLA promises direct “access” to these environments. • Historical Precedent: Astrophysical Journal born after introduction of Spectrograph. EarlySpectrograph

  21. Lab Jet Experiments:Similarity Energy Equations are invariant under change of variables (scales)

  22. “Supernova by Jet”Khokhlov et al • “Plug” of Mg creates collimated flow. • SN driven by jet from core

  23. Experiments on the Gekko laser -> Shock-Cloud collisions Kang, et al.

  24. Paris Observatory April 2001 AMRCLAW based adaptive mesh refinement: resolution cascade 3 levels of refinement, equivalent resolution 800x1600, shown is density logarithm

  25. 2D vs. 3D instability Spherical divergence 2D simulation of SN1987A Muller, Fryxell, and Arnett (1991) Multi-interface coupling Multi-mode instability Experiments at Omega are probing several mechanisms present in supernova explosions

  26. Radiative Cooling Jets! Vz = 200 km/s M > 15 Use W wires, high rate of cooling (proportional to Z)

  27. on the other hand . . . • average clump separation along the flow  y = 10 m  10 % dcrit • average clump separation along the flow  x = 5.32 m  6 % LCD Therefore . . . Designed system is a system of strongly interacting clumps with both global and local evolution strongly affected by clump merging prior to breakup For the clump system implemented in the target design: • critical cloud separation dcrit = 4.2 cloud radii = 105 m • clump destruction length LCD = 3.54 cloud radii = 88 m • clump velocity at breakup vc = 36.5% post-shock velocity  18 km/sec • clump breakup time tCD = 12 ns

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