WHI Data and Modeling Assessment Workshop

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WHI Data and Modeling Assessment Workshop
Working Group 2 Quantifying the solar minimum
heliosphere Group coordinators Leonard
Strachan and Scott McIntosh
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Primary Goals for Working Group 2

• The two main goals for this WG are
• To provide quantitative measures of physical
  properties of the solar atmosphere.
• To provide boundary conditions and constraints
  on coronal and solar wind models.

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WHI Observations

• The data were obtained during 2 Target Observing
  Campaigns and 1 Target of Opportunity Campaign.
• Streamers and origin of the slow wind (Strachan)
  Dates of Observations12-19 Mar, 27 Mar 2 Apr
  2008
• Quiet Sun from chromosphere to corona (McIntosh)
  Dates of
  Observations 10-16 Apr 2008
• Equatorial coronal holes and fast wind
  (Miralles) Dates of
  Observations 29-30 Mar, 3-18 Apr 2008
• Solar irradiance measurements (Woods)
• Dates of Observations Mar Apr 2008
  

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Instrument Teams Involved
A large number of space based and ground
observatories were involved covering the Sun
and heliosphere at multiple wavelengths Hinode/E
IS, Hinode/XRT, Hinode/SOT, SOHO/EIT, SOHO/LASCO,
SOHO/SUMER, SOHO/UVCS, SOHO/CELIAS, SOHO/EPHIN,
SOHO/CDS, STEREO/SECCHI, STEREO/SEPT,
STEREO/PLASTIC, STEREO/COR1/2, TRACE,
HAO/MLSO/Mark4, SMEI, Ooty Radio Telescope,
STELAB/Nagoya IPS system, Nancay Radioheliograph,
ACE/SWICS, NSO/SOLIS, NSO-DST/IBIS
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Expected Outcomes from the Workshop

• Define the set of physical parameters that were
  measured
• Build a physical description of the steady state
  corona at the time of the WHI campaign
• Interface with modeling teams to compare
  empirical measurements with model results for
  observed structures
• Identify missing information that may be needed
  to complete data-model comparisons.

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Summary of WG2 Contributions

• Identified WG2 workshop participants
• Leonard Strachan
• Simon Plunkett
• Samaiyah Farid
• Terry Kucera
• Bernie Jackson
• Scott McIntosh
• Tom Woods
• Don Schmit
• Anyone else?

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Overview Streamer Cavity Observations
TRACE 195 (top left/right) LASCO C2 (bottom
left/right)
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Summary of UVCS Observations
UVCS Instrument Configuration Sit and Stare Obs
10 hrs duration at 1.7 Ro on each day Exposure
time 120 sec Slit length 40 Slit width
14 Spatial bins 56 (along slit) Spectral bins
0.14 Å (LYA) 0.095 and 0.19Å (OVI) Spectral
lines on detector a) H Lya, Fe VIII 1242
Å, N V 1238 Å, S X 1196 Å b) O VI 1032 Å, O
VI 1037 Å, H I 1025 Å, Si XII 521 Å c) in
addition to (b) Si XII 499 Å, H I 972 Å
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Summary of UVCS Observations
Dates 12-19 Mar 2008 27-31 Mar
2008 31 Mar- 2 Apr 2008 Target PA
300o 55o
245o Obs. Heights 1.7-3.3
Rs 1.7 Rs
1.7 Rs
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Empirically Derived Quantities
The following are the streamer quantities to be
determined

• electron density
• WL polarized brightness (MLSO/Mk4, LASCO/C2,
  STEREO/COR1/COR2)
• Radio IPS observations (STELAB, OOTY,etc.)
• Emission measure analysis (EIT, CDS, TRACE)
• Radio brightness temperature (NRT)

• thermal and kinetic temperatures
• Te from spectral line ratios (UVCS, CDS)
• Te from density gradients (MLSO/Mk4, LASCO/C2,
  STEREO/COR1/2)
• Ti (kinetic) from spectral line widths (UVCS)

• bulk outflow velocity
• Doppler dimming (UVCS OVI line ratios)
• Feature tracking in images (LASCO/C2, Mk4,
  STEREO)
• Radio IPS observations with STELAB, OOTY,etc.

• elemental abundances (absolute and from FIP
  ratio)
• spectral line ratios relative to Hydrogen lines
  (UVCS)
• line ratios relative to other elements (UVCS,
  CDS)

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CDS Lines for Temperature and Density
Si XII 520.66 Å Al XI 550.03 Å Fe XIV 334.17 Å
Ca X 557.77 Å Ne VI 558.59/Ne VII 558.61 Å
Al XI 568.12 Å Al XI 568.12 / Ne V 568.24 Å
Fe XI 341.11 Å Si IX 341.95 Å Si X 347.40
Å Fe XIII 348.18 Å Fe XII 352.1/Mg V 352.2
Å Fe XI 352.66 Å Fe XIV 353.83 Å Si X
356.01/356.05 Å Fe XI 358.62 /Ne V, Ne IV 359
Å Fe XIII 359.64/359.84 /Ne V Å Mg X 609.79
Å Si X 624.73/Mg X 624.94 Å O V 616.95 Å He I
548.33 Å Density sensitive ratios Si X 347/
356, Fe XIII 348/ 360, Fe XIV 334 / 353 Å
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Summary of Streamer Observations

• Status of Data Analysis
• UVCS data from WHI week 2 have been put into a
  single data array with spatial coordinates (solar
  X and Y), obs time, background corrected count
  rates. These are used to make intensity maps of
  streamers in different spectral lines.
• What else is needed
• electron densities at each UVCS location
• electron temperature structure in streamer
• expected magnetic field geometry from coronal
  base
• streamer abundances at all heights and in solar
  wind

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Characterizing the Quiet Sun Where is it?

• Detailed study of the response of the quiet
  solar chromosphere, transition region and corona
  to the constantly evolving photospheric magnetic
  field
• Gain reasonable estimates of the energy flux
  through the chromosphere and lower transition
  region.
• Assess the relevance/importance of
  magneto-atmospheric wave energy versus direct
  magnetic energy release in the atmosphere below
  temperatures at which thermal conduction becomes
  significant.

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Characterizing the Quiet Sun Where is it?
Example observations from 10 April 2008
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Solar Irradiance Rocket Observations

• TIMED Solar EUV Experiment (SEE)
• XPS 0.1-34 nm, Dl 8 nm
• EGS 27-194 nm, Dl 0.4 nm
• Solar Radiation and Climate Experiment (SORCE)
• XPS same as on TIMED SEE
• SOLSTICE 115-310 nm, Dl 0.1 nm
• SIM 200-2400 nm, l/Dl 30
• TIM total solar irradiance (TSI)
• SOHO Solar EUV Monitor (SEM)
• 26-34 nm and zeroth order 0-50 nm
• SDO EUV Variability Experiment (EVE)
• Rocket EVE 6-105 nm, Dl 0.1 nm
• Suborbital rocket launched 14 April 08
• NOAA SBUV 200-400 nm

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Is this solar cycle minimum at lower level?

• SOHO VIRGO preliminary analysis suggest that the
  Total Solar Irradiance (TSI) for this solar cycle
  minimum is 0.02 lower than last solar cycle
  minimum
• Also a fairly long cycle (12 years)

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Four Spectra to Prepare for WHI Interval

• Quiet Sun (solar cycle minimum) Reference
  Spectra
• SORCE SIM dates of 9-Nov-2007 5 days
• WHI Quiet Sun dates of Apr 10-16 (Rocket
  14-Apr-2008)
• Active Region Reference Spectra
• Mar 29 5 days from PSPT images (feature areas)
• Compare these new results to model and previous
  reference spectra
• Models SRPM, NRLEUV
• Reference Spectra Thuillier (VUV2002),
  ASTM-E490
• Plan to have these results by Friday