Coronal Magnetic Fields: Plan of Action

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Coronal Magnetic Fields Plan of Action

• Hare and hounds initiative (leader Penn)
• Initiative on instrumental limits (leaders
  Mickey, Penn)
• Initiative on pioneering measurements of magnetic
  fields in the solar corona (Leaders Kuhn, Lin,
  Mickey)
• Initiative on the use of Coronal Magnetic Field
  measurements in theoretical models (Leaders
  Fisher, Roussev, Li)
• Initiative on integration with other measurements
  (leader Hudson?)
• Appendix Other research projects spawned by our
  workshop Measurement of prominence masses and
  geometries Hudson

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Hare and Hounds Initiativeleader Penn

• 1. Generate coronal models active region,
  flux rope, helmets, CMEs, filaments B(x,y,z),
  n(x,y,z), T(x,y,z) (15 Jan)
• Global analytic and plane parallel atmosphere
  (BC)
• Aulanier filament models and BC Low filament
  models
• Use potential field or MHD simulation, then add
  better coronal energy balance physics post-facto
  (Lundquist, Fisher, Alexander)

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Hare Hounds (contd)

• 2. Convert models to I(x,y,lam,pol) (Lin,
  Judge? Casini?, Gibson?) (15 Mar)
• Collisions modifying pol signal
• Projection
• NRL (physical and intensity calculation)?

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Hare Hounds (contd)

• 3. Add telescope, compute data, analyze (15
  Apr)
• Kuhn (Solar-C) gallery of diff. structures
• Penn (ATST)
• Tomczyk (COMP)

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Initiative on instrumental limitsleaders
Mickey, Penn

• Definitions
• Class 1 observations use the instrument as a
  coronagraph (no magnetic information), look in
  continuum, see ne distribution
• Class 2 observations use the integrated IR
  coronal emission line to look at linear
  polarization (related to transverse field
  direction) and in total intensity intensity
  defines where the corona is emitting in, e.g.,
  FeXIII compared to all coronal plasma
• Class 3 observations Measure Zeeman splitting
  resolve line profile and have high polarization
  sensitivity.

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Initiative on instrumental limits (contd)

• Action a group of experimentalists (Penn,
  Mickey, H. Lin, Kuhn) will quantify, for the
  Solar-C telescope, what spatial temporal
  resolutions are practical feasible for given
  sensitivities in each of the 3 classes of
  observation.

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Initiative on Pioneering Coronal Magnetic Field
msmts (LeadersKuhn, Lin, Mickey)

• Primary Goal Answer this question Is there
  conclusive evidence for a flux rope in corona
  before eruption? If so, what is the field
  strength, twist, and length of the rope?

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Initiative on Pioneering Coronal Magnetic Field
msmts (contd)

• Observing plan for primary goal
• systematic measurement of the linear and circular
  polarization of long-lived prominences that cross
  both limbs of the Sun. Frequently, these are
  tilted w/r to azimuthal direction. Getting
  observations on both limbs allows for a possible
  reconstruction of the desired flux rope
  parameters. H. Lin, Kuhn, Mickey
• Observe prominences in H? with the IVM Mickey,
  others?

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Initiative on Pioneering Coronal Magnetic Field
msmts (contd)

• Secondary observational goals
• Measure linear and circular polarizations in a
  helmet streamer
• Look for polarization signatures of
  quasi-separatrix surfaces in the solar corona
• Examine the polarization structure near a coronal
  hole-streamer boundary

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Initiative on Pioneering Coronal Magnetic Field
msmts (contd)

• Long term goal 3-d synoptic magnetic field maps
  of the large scale corona. This would be
  extremely valuable for comparison with large
  scale models of the corona (such as
  source-surface models).
• Solar-C observations will provide a test bed of
  concepts for coronal observations from ATST

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Initiative on the use of coronal magnetic field
measurements in theoretical models (Leaders
Fisher, Roussev, Li)

• Observations with Solar-C that could test
  models of flux-rope like structures
• (1) filament models (e.g. Aulanier)
• (2) flux rope models e.g. Roussev-Titov/Demouli
  n
• (3) analytic models of BC Low. Inverse versus
  normal filament topology
• (4) filament models that are not highly
  twisted - eg Dahlburg Antiochos(??)
• Action Get model originators to Identify the
  features of these models that would allow for
  observational discrimination

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Initiative on the use of coronal magnetic field
measurements in theoretical models (contd)

• Use coronal field measurements to test models
  of helmet-streamer and active region structures
  
• (1) source-surface models (Li)
• (2) MHD solar-wind/helmet streamer models
  (Michigan, Ledvina, CISM efforts of Mikic
  Linker)
• (3) active region models (Abbett/Fisher/Lundqu
  ist),

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Other measurements to coordinate with coronal B
measurements (leader Hudson?)

• TRACE (field lines) develop algorithm for using
  xray images to reconstruct field line curves
  Hudson??
• Coordinate obs. with UVCS to get T,n,v
  diagnostics to go along with the B msmts Jing
  Li
• Radio msmts tie down field in active regions
  BBSO? Owens Valley? Dale Gary?
• Energetic particle measurements Hudson?
• Chromospheric vector magnetograms Metcalf??
  Leka??
• Action item Get confirmed leader for this
  initiative and finish identifying people who want
  to do these things.

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Appendix Measurement of prominence masses and
geometries (leader Hudson)
Overview of techniques 1.1 H-alpha 1.2 EUV
absorption 1.3 Thomson scattering 1.4 Micro/mm
free-free emission 2. Characterization of masses
2.1 Quiescent prominences 2.2 Erupting
prominences 2.3 Active-region prominences 3.
Filament masses related to CMEs and flares 3.1
Statistics 3.2 Morphology 3.3 Transformation
during eruption