Abundances in the Solar Atmosphere
and in the Solar Wind
Tuesday PM and Wednesday AM
Enrico Landi (University of Michigan)
Daniel Wolf Savin (Columbia University)
How to collapse 5 hours of talks and
discussion into a 15 minute summary
• Cleary that’s not possible.
• I’ve picked some highlights to illustrate the subjects
• Hopefully this will give a flavor of the Session.
• Apologies in advance to the speakers for mangling what
they presented in the Session.
Spectroscopic Determination of Solar
Atmosphere Abundances (Peter Young)
FIP bias (corona/photosphere)
• Abundances say something about solar physics
First Ionization Potential (eV)
FIP bias measurements in the solar
corona show significant variability
• Coronal holes
– no FIP bias (reasonably solid result)
• Quiet Sun
– FIP bias = 2 to 4
– Transition region not consistent with corona
• Active regions
– FIP bias seems to vary with age of structures
– Different structures in same AR have different biases
• Interpreting these results is hindered by a lack of
quantitative theoretical models.
Solar Wind Heavy Ions Over Solar Cycle
23: ACE/SWICS Measurements (Sue Lepri)
• How much do distribution and fractional contribution
from each type of wind changes over solar cycle?
• Goal is to study the solar cycle evolution of both the fast
and slow solar wind using ecliptic plane in-situ data.
• How do plasma parameters, charge state distributions
and elemental composition evolve with solar cycle?
• Do the fast and slow wind properties evolve in the same
ACE/SWICS elemental composition
measurements over solar cycle 23
• Heavy elements depleted towards solar minimum, with
slow wind becoming more depleted than fast.
• This is in line with predictions for enhanced Coulomb
drag, predicted for lower coronal densities.
• FIP bias preserved in slow wind, ordering changes in fast.
• Abundances behavior suggests reduced proton flux from
corona & less efficient acceleration of heavy ions.
• Interpreting these results is hindered by a lack of
quantitative theoretical models.
Poster presentations of other in-situ
• Polar and equatorial coronal hole winds at solar
minima: ACE & Ulysses observations
– P81: Liang Zhang
• Correlation of heavy ion dropouts with heliospheric
and magnetic structures
– P83: Micah Weberg
PLENARY: Elemental Fractionation in the
Solar Corona and Wind (Martin Laming)
• FIP Effect due to action of ponderomotive force in
chromosphere acting on ions, not neutrals.
• Coronal loop acts as resonant cavity for Alfvén waves.
• Alfvén waves can have either chromospheric or coronal
• Waves originating in loop (generally resonant) imply a
positive FIP effect as well as He depletion.
Ponderomotive model does good job of
reproducing FIP effect in slow & fast wind.
Variations of Elemental Composition in
the Solar Wind and SEPs (Kuen Ko)
Variations of Elemental Composition in
the Solar Wind and SEPs (Kuen Ko)
• Abundance variations w/corresponding changes at
origin are critical to understand solar wind formation.
• Such studies need accurate 3D global coronal magnetic
field data.
• Spectroscopic data needed for wide range of
temperatures and of both low and high FIP elements.
• Need also spectroscopic and in-situ data that match in
space and in time.
Chromospheric abundances from solar
flare gamma-ray spectra (Gerry Share)
Simulation of S-Web Corridor Dynamics:
Implications for Solar Wind (Aleida Young)
• What is the S-Web theory for slow solar wind?
• Why is it critical for interpreting solar wind
• Current efforts to model S-web corridors.
• See P083 for more details.
SOHO CELIAS MTOF (James Weygand)
The DRUTHERS Mission
Uncovering the
Rounding the
Kamikaze Mission

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