Synoptic maps and applications

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Synoptic maps and applications

• Yan Li
• Space
  Sciences Laboratory
• University of
  California, Berkeley, CA
• HMI team meeting, Jan 27, 2005,
  Stanford

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Synoptic frame
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Basics of the PFSS Model

• Useful attributes of the model include
  open/closed field regions (e.g. coronal hole
  footprints for a specific photospheric field
  description).
• The last closed field lines form the helmet
  streamer belt whose cusps at the source surface
  define the base of the heliospheric current sheet.

Source Surface
(Y. Li)
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• PFSS model gives
• Coronal holes
• Coronal field lines
• Source surface neutral lines
• http//sprg.ssl.berkeley.edu/mf_evol/

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MDI
WSO
MWO
NSO
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Newly opening field lines
Li et al., 2001
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This long term record of longitudinally averaged
synoptic maps from the MWO magnetograph shows the
relative phasing of the solar polar field
reversal and the active region polarity reversal
(Hale cycle). This has important implications for
the likely CME initiation process
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Luhmann et al., JGR, 2002

• Solar cycle variation of solarwind source,
  color-coded by photospheric magnetic field
  polarity. Red designates radially outward fields,
  and blue designates radially inward fields.

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Luhmann et al., JGR, 2002

• Solar cycle changes of Solarwind source at
  the photosphere. Photospheric field strength at
  the foot points are color coded. Red designates
  strengths gt30 G, blue designates strengths lt10 G,
  and green denotes intermediate values.

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Luhmann et al., JGR, 2002

• Solar cycle variation of solar wind velocity
  inferred using the Wang-Sheeley-Arge model. Red
  designates inferred speeds gt550 km/s, blue
  designates inferred speeds lt350 km/s, and green
  denotes intermediate values.

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U of Colorado and UCB (Arge et al., JASTP,
2004) Solar Event May 12, 1997 Solar Wind and
Stream Context
Stream source region
May 12th CME
Stream source region
(suggests solar wind stream following the ICME
comes from the southern hemisphere)
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• To study coronal field configuration and topology
  of CME cases.

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• To study field line connections among active
  regions.

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A simple loop on Dec. 26, 97.
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Complex loops, named x-loops, on Sept 9, 1998.
PFSS lines compare well with sxt loops.
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Longterm behaviour of TLSs
Ten years of data from 1992 to 2002 are combined
to give the display. Top green shows the points
where the magnetic field strength is above 50G,
and where we start to trace field lines. Middle
red shows the closed field lines starting from
the strong field regions, our proxy for TLSs,
which to some extent take on the solar cycle
butterfly trend. Bottom red shows a subset of
closed field lines that both ends are in strong
field regions.
Solar Minimum Maximum
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• To be the initial condition for MHD global models.

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CR1935 ZUES coronal (from S. Ledvina, SSL/UCB)
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Problems encountered

• Data gaps,
• Polar regions,
• Resolution,
• Cadence,
• Noise.