docObservations and Magnetohydrodynamic Modeling of Supra
download 
Report Transcription
Observations and Magnetohydrodynamic Modeling of Supra
Observations and Magnetohydrodynamic Modeling of Supra-Arcade Plasma Sheets! Roger B. Scott! David E. Mckenzie! Dana W. Longcope! ! Montana State University! ! This work was partially supported by NASA under contract NNM07AB07C ! with the Smithsonian Astrophysical Observatory, and Living with a Star grant NNX14AD43G! Modeling the Supra-Arcade Region through…! • Analytical model of magnetized flow past a circular boundary (Peristaltic Pumping - 2012).! • Assimilation of observational data into Hybrid MHD code (DAFT - pending).! • Numerical simulation of magnetized flow past a circular boundary with arbitrary plasma-beta (ConFlow - pending).! Peristaltic Pumping! (magnetically confined hydrodynamic flow)! • A circular Intrusion (reconnected flux?) deforms the pre-existing potential field as it descends.! • Plasma is treated as flowing upward relative to the intrusion.! • The solution along individual field lines is found through application of a 1D, quasi-analytic, hydrodynamic model.! Peristaltic Pumping! (magnetically confined hydrodynamic flow)! Peristaltic Pumping! (magnetically confined hydrodynamic flow)! ConFlow! Conformally Mapped 2D MHD Simulation.! ConFlow Simulation! Laminar Solutions! beta ~ 0, Ms ~ 0.3! ConFlow Simulation! Laminar Solutions! beta ~ 0, Ms ~ 2.1! Magnetically Confined Shocks! (signatures and implications)! ConFlow Simulation! Magnetically Confined Hydrodynamic Shocks! beta ~ 0, Ms ~ 1.4! ConFlow Simulation! Magnetically Confined Hydrodynamic Shocks! beta ~ 0.5, Ms ~ 1.4! Ballistic Shocks! (signatures and implications)! ConFlow Simulation! Ballistic MHD Shocks! beta ~ 2.0, Ms ~ 1.4! ConFlow Simulation! Ballistic MHD Shocks! beta ~ 0.5, Ms ~ 2.1! Parameter Survey! • ! • Fluid dominant if beta large or Ma large.! • Laminar flow exists for supersonic scenario beta small and Ma small.! Summary! • Numerical simulations corroborate analytical model.! • Columnated shocks and supersonic laminar solutions observed.! • • Columnated shocks exhibit entrained low density tail.! • • beta <= 1 sufficient ! Slowly increasing upstream density may lead to significantly rarefied tail region.! Low beta ballistic regime discovered.! • Ms2 * beta > 1, shocks are not columnated.!