Understanding Magnetic Eruptions on the Sun and their Interplanetary Consequences A Solar and Heliospheric Research grant funded by the DoD MURI program George H. Fisher, PI Space Sciences Laboratory University of California, Berkeley

Goal Develop a state-of-the-art, observationally tested 3-D numerical modeling system for predicting magnetic eruptions on the Sun and the propagation of Coronal Mass Ejections (CMEs).

Approach Perform in-depth, coordinated space and ground based observations of magnetic eruptions and Coronal Mass Ejection (CME) propagation Understand the physics of how magnetic eruptions are triggered and powered Develop numerical models for the initiation and propagation of CMEs and the acceleration of Solar Energetic Particles (SEPs) Couple together the observationally tested models of the Sun and Heliosphere

Institutions of Solar Multidisciplinary University Research Initiative Team UC Berkeley Big Bear Solar Observatory (NJIT) Drexel University Montana State University Stanford University UC San Diego University of Colorado University of Hawaii University of New Hampshire

Overview of Solar MURI 1.Active Region Emergence: Fisher & Abbett (UCB), LaBonte & Mickey (UH), Canfield (MSU), Liu (Stanford), Gallagher, Wang & Goode (BBSO) 2.Effects of Large Scale Field and Solar Cycle Evolution: Hoeksema, Scherrer, & Zhao (Stanford), Ledvina & Luhmann (UCB), Martens (MSU), Goode, Wang & Gallagher (BBSO) 3.Inner Corona: Forbes (UNH), MacNeice (Drexel), Abbett, Ledvina, Li, Luhmann & Fisher (UCB), Kuhn & H. Lin (UH), Canfield & Longcope (MSU), Hoeksema, Scherrer & Zhao (Stanford) 4.Outer Corona, Solar Wind, SEPs: Odstrcil (CU), Jackson & Hick (UCSD), MacNeice (Drexel), Li, Luhmann & R. Lin (UCB), Lee (UNH) 5.Geoeffects: Luhmann & R. Lin (UCB), Odstrcil (CU), Hoeksema & Zhao (Stanford)

The MURI workshops Our problems are multi-disciplinary and larger in scope than what an individual scientist or a small group can cope with A helpful step is to organize highly focused workshops to better define our problems and propose concrete, do-able research projects that help us achieve our overall goals

MURI workshops held so far: Paramesh code-coupling workshop at GSFC (held July 2001, organized by Peter MacNeice) Vector magnetogram workshop at UCB (held in April 2002, organized by Canfield & Fisher) Synoptic Magnetic Maps workshop in Boulder (held April 2002, organized by Bernie Jackson) CME numerical experiments workshop at UNH (held May 2002, organized by Forbes) Measuring coronal magnetic fields: How can we make best use of these measurements for understanding CME eruption? (held Nov in Honolulu, organized by Kuhn) CMEs and solar energetic particles (held March 2003, organized by Kota)

Example of results from one of these workshops: The vector magnetogram workshop Selected our MURI events for further study: May and May (Li, Canfield) Analysis of vector magnetograms and construction of force-free-fields for initial conditions (Regnier, Liu) Development and testing of photospheric velocity determination methods (Longcope, Welsch, Fisher, Abbett) Performance of MHD simulations using initial conditions from Regnier and velocity driving from Longcope (Abbett)

UC Berkeley MURI team FY03 highlight: Modeling eruptive solar active region AR-8210 Space weather is driven by magnetic changes on the Sun -- and a physics-based modeling system with predictive capability must incorporate time-dependent solar magnetic field measurements with self-consistent driving velocities for the erupting solar plasma. The UC Berkeley MURI team is modeling active region AR-8210, which produced several Coronal Mass Ejections (CMEs) around 1 May 1998, and for which we have extensive vector magnetic field measurements. This data has been reduced and analyzed by Dr. Stephane Regnier at Montana State University. He then generated a nonlinear force-free field model of the coronal magnetic field to be used as initial conditions for time-dependent MHD models that are being run by Dr. William Abbett at UC Berkeley. The nonlinear force-free field model is depicted here, with a few of the magnetic field lines drawn and with the coronal field lines shown in green. The bottom frame shows a reconstructed X-ray image of AR-8210 based on a physics-based energy balance model developed by UC Berkeley physics graduate student Loraine Lundquist. She has used the force-free model of Dr. Regnier, plus an empirical relationship between magnetic flux and coronal heating derived by UC Berkeley PI Dr. George Fisher, to reconstruct the temperature and density in the solar corona over AR Her reconstruction compares favorably to an actual image from the Yohkoh spacecraft taken at about the same time. Thus, MURI models draw ever closer to reality. Vertical component of magnetic field; B & W represent opposite polarities Reconstructed X-ray image of AR-8210 Non-linear force-free field model