Understanding Magnetic Eruptions on the Sun and their Interplanetary

Consequences

A Solar and Heliospheric A Solar and Heliospheric Research grant funded by the Research grant funded by the

DoD MURI programDoD MURI program

George H. Fisher, PIGeorge H. Fisher, PI

Space Sciences LaboratorySpace Sciences Laboratory

University of California, BerkeleyUniversity of California, Berkeley

Goal

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

Motivation

The Sun drives the magnetic eruptions that The Sun drives the magnetic eruptions that initiate violent space weather events. The initiate violent space weather events. The mechanisms that trigger and drive these mechanisms that trigger and drive these eruptions are the least understood aspects of eruptions are the least understood aspects of space weather. A better physical space weather. A better physical understanding of how magnetic eruptions understanding of how magnetic eruptions occur on the Sun and how the disturbances occur on the Sun and how the disturbances propagate through the Heliosphere will surely propagate through the Heliosphere will surely lead to more accurate and longer range lead to more accurate and longer range forecasts.forecasts.

Approach

Perform in-depth, coordinated space and Perform in-depth, coordinated space and ground based observations of magnetic ground based observations of magnetic eruptions and CME propagationeruptions and CME propagation

Understand the physics of how magnetic Understand the physics of how magnetic eruptions are triggered and powerederuptions are triggered and powered

Develop and test numerical models for the Develop and test numerical models for the propagation of CMEs and the acceleration of propagation of CMEs and the acceleration of Solar Energetic Particles (SEPs)Solar Energetic Particles (SEPs)

Couple together the observationally tested Couple together the observationally tested models of the Sun and Heliospheremodels of the Sun and Heliosphere

Institutions of Solar Multidisciplinary University Research Initiative Team UC BerkeleyUC Berkeley Big Bear Solar Big Bear Solar

Observatory (NJIT) Observatory (NJIT) Drexel UniversityDrexel University Montana State Montana State

UniversityUniversity Stanford UniversityStanford University UC San DiegoUC San Diego University of University of

ColoradoColorado University of HawaiiUniversity of Hawaii University of New University of New

HampshireHampshire

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, 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), Luhmann & R. Lin (UCB), Lee (UNH)

5. Geoeffects: Luhmann & R. Lin (UCB), Odstrcil (CU), Hoeksema & Zhao (Stanford)

New technology to measure magnetic fields in the corona

Infra-red lines Infra-red lines formed in solar formed in solar corona can be corona can be used to measure used to measure magnetic fields. magnetic fields. (H. Lin, J. Kuhn, (H. Lin, J. Kuhn, UH)UH)

Eruptive Flare of Aug. 5, 1999 (BBSO)

Movie of Movie of Limb Limb Observations Observations in Hin Hof a of a classic 2-classic 2-ribbon flare, ribbon flare, taken by taken by Johns-Krull Johns-Krull and Fisher and Fisher (UCB)(UCB)

Important Ingredients in the Genesis of Magnetic Eruptions

Flux emergenceFlux emergence Twist (helicity)Twist (helicity) Topology changesTopology changes

Flux Emergence in an Active Region

Coupling Coupling between the between the ANMHD code ANMHD code describing the describing the solar interior solar interior and ZEUS3D and ZEUS3D code for code for modeling the modeling the corona above corona above an active an active region.region.

Sigmoids: The Role of Twisted Fields in Magnetic Eruptions

Sigmoidal Sigmoidal structures in structures in the corona the corona seem to be a seem to be a precursor to precursor to magnetic magnetic eruptionseruptions

Sigmoidal Field Lines from a Twisted Emerging Active Region

Coronal field Coronal field lines computed lines computed with the ZEUS3D with the ZEUS3D MHD code, MHD code, driven at the driven at the photospheric photospheric boundary by flux boundary by flux emergence emergence computed with computed with the ANMHD the ANMHD code. The S-code. The S-shaped field shaped field lines derive from lines derive from a modestly a modestly twisted flux tube twisted flux tube rising through rising through the solar interior.the solar interior.

Changing Field Line Topology: A storm Precursor?

Orientation of Orientation of coronal arcade coronal arcade agrees with that agrees with that of flux rope of flux rope model fitted to model fitted to WIND (ICME) WIND (ICME) observationsobservations

Two different ideas about how topology changes drive magnetic eruptions:

Tether cuttingTether cutting BreakoutBreakout

Simulations of Breakout Model

Movie: 2 ½ d Movie: 2 ½ d MHD MHD simulations simulations using AMR using AMR (MacNeice & (MacNeice & Antiochos)Antiochos)

3d ICME propagation in Heliosphere of July 14 2000 event

Movie Movie showing showing Reconstructed Reconstructed density in density in Heliosphere Heliosphere from IPS from IPS observations observations by Jackson & by Jackson & Hick (UCSD)Hick (UCSD)

Simulations of ICME propagation

MHD simulations of MHD simulations of solar disturbances solar disturbances propagating into propagating into the Heliosphere the Heliosphere can be followed can be followed from tens of solar from tens of solar radii out to 1 AU. radii out to 1 AU. Shown here is a Shown here is a depiction of a depiction of a modeled modeled disturbance at 1 disturbance at 1 AU (Odstrcil, CU)AU (Odstrcil, CU)

Conclusions

The quality and quantity of Solar and The quality and quantity of Solar and Heliospheric observations now Heliospheric observations now available, in conjunction with rapid available, in conjunction with rapid increases in computing power make this increases in computing power make this the right time to develop a coupled the right time to develop a coupled Solar and Heliospheric model. We Solar and Heliospheric model. We expect to make great progress toward expect to make great progress toward our goal over the next 5 years.our goal over the next 5 years.