Session 6 Key Questions for Understanding This Unusual Solar Minimum

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Session 6Key Questions for Understanding This
Unusual Solar Minimum

• Alan Gabriel
• Todd Hoeksema
• Janet Luhmann
• Bill Matthaeus
• Neil Sheeley

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Key Questions for Understanding This Unusual
Solar Minimum

• What is unique?
• Delayed Onset
• Asymmetry
• Meridional flow
• Polar Field ?
• Coronal Holes
• Morphology
• Mass/Scale Height

Irradiance Small-scale emergence Solar
Wind Heliosphere CMEs / SEPs Cosmic Rays And more
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Key Questions for Understanding This Unusual
Solar Minimum

• Our understanding and measurement of the system
  is much improved as it absolutely must be to
  make progress on a complex and highly
  interconnected problem

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Key Questions for Understanding This Unusual
Solar Minimum

• We need to study this cycle in the context of
  previous cycles the more the better.
• This is not our fathers cycle but our
  Grandfathers cycle

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• Comparison of
• Large-Scale
• Corona in
• Cycles 21 23
• Panels spaced
• By 12 rotations.
• CYCLE 23
• Longer
• Fewer Contours
• Gradual Flattening
• Structures Persist
• More Dipolar in
• Declining Phase
• Structures Persist
• Thanks to Weak Poles

Cycle 21
Cycle 23
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Antisymmetric Zonal
Old Polarity Surge 2003/4
Symmetric Zonal
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Key Questions for Understanding This Unusual
Solar Minimum

• Some care must be taken in defining concepts
  your minimum may not be my minimum (etc.)

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Key Questions for Understanding This Unusual
Solar Minimum

• What are the key measurements and theoretical
  developments required so that we wont be
  surprised when the next cycle rolls around?

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Perspective Comes from Taking the Long View
From Wikipedia website
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What lies ahead?

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• Comparison of
• Large-Scale
• Corona in
• Cycles 22 23
• Panels spaced
• By 12 rotations.
• Cycle 23
• Fewer Contours
• Slower Flattening
• Structures Persist
• Thanks to Weak Poles
• Both Dipolar During
• Reversal

Cycle 22
Cycle 23
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We have recently achieved unprecedented ability
to observe, understand, and model the physical
connections throughout the heliospheric system
based on measurements of the solar magnetic
field. Corroboration comes from images on SOHO
and STEREO, in-situ measurements on SOHO, WIND,
ACE, STEREO , other data from Hinode, TRACE,
RHESSI, neutron monitors, etc. But does this
tell us how the cycle will evolve?
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Best SSNmax empirical predictions are those
based on rise time of cycle
?
Figures from MSFC website and from Cameron and
Schussler, ApJ 2008
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A way to get and relate variable polar fields
and IMFs via surface transport and changing
meridional flow
Wang et al. , ApJ 2005
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Whats missing essential dynamo processes in
the Sun determining flux generation, emergence
and transport
Figures Brun and Toomre, ApJ 2002, SOHO website