1 / 13

Modeling Emerging Magnetic Flux

Modeling Emerging Magnetic Flux. W.P. Abbett, G.H. Fisher & Y. Fan. Sub-surface Modeling. ANMHD --- 3D MHD in the anelastic approximation Pseudo-spectral technique

avian
Download Presentation

Modeling Emerging Magnetic Flux

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Modeling Emerging Magnetic Flux W.P. Abbett, G.H. Fisher & Y. Fan

  2. Sub-surface Modeling • ANMHD --- 3D MHD in the anelastic approximation • Pseudo-spectral technique • Code is mature --- optimized for use on both shared and distributed memory machines (eg. IBM SP, SGI Origin 3800), as well as single-processor workstations • Numerical algorithm allows for extensive exploration of parameter space

  3. ANMHD Examples: LHS --- magneto-convection and the local solar dynamo; RHS --- emerging magnetic flux.

  4. Of interest: Highly twisted, knotted configurations (Linton, Fan, Fisher) Kink unstable magnetic flux tube rising through a stratified model CZ (LHS using ANMHD -- Fan et al.) and evolving in a non-stratified domain using a periodic spectral code (RHS -- Linton).

  5. Delta Spot Active Regions modeled as buoyant, initially kink-unstable flux tubes that emerge through CZ (Linton et al.) Q: Is emerging flux (especially in highly sheared configurations) an important component of the CME initiation process?

  6. ANMHD --- Summary • Provides numerous, simulated active region datasets that can be used to provide self-consistent, depth dependent sub-photospheric velocity and magnetic fields for input into global coronal models • Future development plans: SANMHD (3D spherical ANMHD --- Bercik)

  7. Modeling the Corona • PARAMESH: A domain decomposition, adaptive mesh refinement (AMR) framework developed by MacNeice et al. and distributed by GSFC • Zeus3D: A staggered mesh finite-difference (non-relativistic) MHD code originally developed by Stone, Norman, and Clarke and publicly distributed by NCSA • ZeusAMR: A fully compressible 3D MHD code with AMR which resulted from a merge of PARAMESH with a modified version of Zeus3D

  8. Local Zeus3D (no AMR) flux emergence calculation

  9. Example of driving a ZeusAMR coronal simulation with an ANMHD generated lower boundary. True “code coupling” can be achieved using the PARAMESH framework.

  10. ZeusAMR Progress: Tasks Completed • Merged Zeus3D with PARAMESH v2.x (decomposition technique optimized for SGI shared memory architectures) • ZeusAMR transport step no longer directionally split (Fan) • ZeusAMR written to enhance portability: the NCSA editor and input decks are eliminated in favor of more modern, portable preprocessors and I/0. • Incorporated boundary conditions and refinement criteria appropriate for simulating flux emergence into the low corona • Added option to include the “Boris Correction” • Incorporated an approximate treatment of transition region heating and cooling terms

  11. ZeusAMR: Tasks Nearly Complete • Implement and test the polar and lower radial boundary conditions when running 3D MHD simulations in spherical coordinates • Incorporate explicit resistivity into the code • Develop a user-friendly means of incorporating an initial global coronal atmosphere into a pre-defined, ZeusAMR block structure

  12. ZeusAMR: Future development • Upgrade PARAMESH routines to v3.0 (more efficient mpi treatment for distributed memory architectures) • Add optically thin radiative cooling and conduction along fieldlines to the equation of internal energy • Incorporate the improved MoC algorithm, and the two temperature treatment of Clarke

  13. Summary: ANMHD can provide a variety of simple (to more complicated) datasets to incorporate into the boundaries of global (or local) simulations of the corona. Different configurations can Be readily generated; the Images on the left were Calculated on a 1.2GHz Athlon PC in ~8 hours

More Related