UCB MURI Team Introduction

1
UCB MURI Team Introduction

• An overview of ongoing work to understand a well
  observed, eruptive active region, along with
  closely related studies..

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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

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Motivation

• Magnetic field evolution on the Sun is the
  engine that drives magnetic eruptions. The
  mechanisms that trigger and drive these eruptions
  are the least understood aspects of space
  weather. A better physical understanding of how
  magnetic eruptions occur on the Sun will surely
  lead to more accurate and longer range forecasts.

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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).

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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

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Overview of Solar MURI

• 1. Active Region Emergence Fisher Abbett
  (UCB), Jing Li, Mickey (UH), Canfield Regnier
  (MSU), Liu (Stanford), Moon, Wang Goode (BBSO)

2. Effects of Large Scale Field and Solar Cycle
Evolution Hoeksema, Scherrer, Zhao (Stanford),
Li, Ledvina Luhmann (UCB), Martens (MSU),
Goode, Wang Moon (BBSO)
3. Inner Corona Forbes (UNH), MacNeice (Drexel),
Abbett, Ledvina, Li, Luhmann, Lundquist Fisher
(UCB), Kuhn H. Lin (UH), Canfield Longcope
(MSU), Hoeksema, Scherrer Zhao (Stanford)
4. Outer Corona, Solar Wind, SEPs Odstrcil (CU),
Jackson, Dunn Hick (UCSD), MacNeice (Drexel),
Luhmann R. Lin (UCB), Lee (UNH)
5. Geoeffects Luhmann R. Lin (UCB), Odstrcil
(CU), Hoeksema Zhao (Stanford)
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Current team focus Numerical models of a real,
eruptive active region AR 8210 May 1, 1998

• A real forecast of solar weather requires that
  models incorporate time dependent magnetic data
• There is no existing capability to do this we
  must develop it
• We have identified a series of new problems which
  must be solved, and are developing new algorithms
  to tackle them

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How do we connect real, time dependent magnetic
data measured on the Sun to MHD models of the
solar corona?

• We must first understand the physics connecting
  flux evolution below the photosphere to that
  above the photosphere.
• Bill Abbett will describe our work in this
  research area.

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How do we determine initial conditions for an MHD
simulation in the solar corona?

• Must first reduce convert measurements of linear
  and circular polarization to magnetic field
  vectors measured along the surface of the Sun
• Must use these data to construct nonlinear
  force-free fields or magnetohydrostatic
  equilibria above the photosphere and into the
  corona. Stephane Regnier will describe this part
  of the project.

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The MHD equations require a knowledge of the 3-d
velocity field at the lower boundary, but this
information is not generally available. How do
we solve this problem?

• Line of sight velocity information could be
  measured from Stokes I profile data
• Local Correlation Tracking (LCT) can in principle
  be used to measure horizontal flow fields
• Dana Longcope has developed a new method for
  determining both v? and vz from the magnetic
  induction equation
• Brian Welsch will describe our team efforts in
  this area.

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How do we connect coronal evolution in an active
region to the dynamics of the large scale corona
and heliosphere?

• Coronal model must couple the active region scale
  to global scales
• Coronal model must couple to heliospheric models
• Steve Ledvina will describe our efforts in this
  area.

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Other techniques for studying large scale coronal
context and heliospheric evolution

• The use of source-surface models to describe how
  active regions affect the global corona will be
  described by Janet Luhman
• and Yan Li will describe her survey on ICME
  properties.