WHI Working Group 4

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WHI Working Group 4
CR 2068 March 20 - April 16, 2008

• WHIs science goals
• Characterize the 3-D solar minimum heliosphere
• Trace the effects of solar structure and
  activity through the solar wind to the Earth
  and other planetary systems

WHIs method Synoptic observing programs
broad heliospheric coverage, provide context
and baseline measurements Targeted observing
campaigns coordinated observations run
during CR 2068 Observational input from 27
solar, 19 heliospheric, and 21 geospace
instruments
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WHI WG 4 Transients Tracing CMEs from Sun to
Earth and Beyond Group coordinator David Webb

• TOPICS
•  
• Origins/Initiation (Active regions/Filaments/Prom
  inences)
• Multi-spectral and multi-distance (from Sun)
  analyses
• CME Event list
• WHI Data is put under WG4
• Specific events (presentations)
• - March 25 (EL AR989) Simon Plunkett (WL
  SOHO, SECCHI)
• Nat Gopalswamy (Radio type II, wave)
• - April 9 (WL- AR989) Samaiyah Farid
  (multi-spectral, prom. eruption, current
  sheet STEREO-Hinode Study Event)
• - AR 10989 vs 10987 and 10988 other
  regions/filaments
• - Other events e.g., March 22, April 4,
  post WHI?
• - April 26-29 (SC-AR992) Sun-STEREO-B
  connection event
• - Solar wind, in-situ obs./models (J.
  Gosling, B. Jackson,
• T. Galvin, D. Odstrcil, A. Reinard, P. Schroeder)

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WHI CME List
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WHI WG 4 Participants
Samaiyah Farid Toni Galvin Holly Gilbert Nat
Gopalswamy Jack Gosling Bernie Jackson Terry
Kucera Yan Li Pat McIntosh Simon
Plunkett Giannina Poletto Kathy Reeves Pete
Riley Alphonse Sterling Barbara Thompson Angelos
Vourlidas Dave Webb
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WHI Working Group 4

•  
• Connections with topics of WG 5 on Global
  evolution for rotations surrounding WHI
  (Gordon Petrie)
• - Sub-surface flows/flux emergence
• - Appearance of active regions
• - Tilt of current sheet
• - Large-scale neutral line/filament channel
  evolution
• - Heliospheric Current Sheet evolution
• - Magnetic sector boundary structure
• - Geospace characteristics

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WHI Working Group 4

• Connections with topics of WG 2 Quantifying the
  solar minimum heliosphere (Leonard Strachan
  and Scott McIntosh)
• - b) Streamers/ cavities/ slow wind
• Connections with topics of WG 3 Tracing
  (non-transient) structures from Sun to Earth
  and beyond (Sarah Gibson, Toni Galvin Tim
  Fuller-Rowell) - Corotating Interaction
  Regions Origins and Impacts
• WHI vs. WSM (Whole Sun Month)
• - Are there common consequences of
  "near-solar-minimum" solar boundary on
  heliophysical system-- or
• - Is this a qualitatively different minimum
  than the last? - WHI vs. WSM CMEs/Active
  region/Large scale structure evolution
• WSM very quiet, little activity vs WHI

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WHI CMEs
60 transients observed by SOHO
(LASCO), STEREO (SECCHI) and/or
SMEI during WHI However, no major
ejecta/magnetic clouds at Earth (geoactivity) or
STEREO-A, -B So, WHI CMEs primarily
studied via remote sensing observations
CME on 25 March 2008 in EIT - Mk4 - LASCO C2
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(m, IP)
Discussed next by Simon Plunkett
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Discussed next by Samaiya Farid
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Post-WHI CME 26-29 April 2008 Our only Sun-1
AU Connection Event?

• Arcade, dimming, EIT wave, type II (m), halo CME
  ST-B, LASCO
• Near Sun-center for
• STEREO-B Earth
• Small SEP at ST- B on 26 April MC at ST-B on
  29 April

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Post-WHI CME 26 April 2008 NOAA SWPC Weekly
Report
Space Weather Highlights SEC PRF 1704 21
27 April 2008 29 April 2008 Solar activity
was very low. Region 992 (N13W17, L 275,
class/area, Cso/040 on 23 April) formed on the
disk on 22 April, but decayed to a spotless plage
region by 25 April. On 26 April, a B3/Sf flare
was observed at 1408 UTC from an unnumbered area
of spotless plage near N08E09. The flare was
associated with a wave that was visible in EUV
imagery on STEREO and SOHO, a Type II radio sweep
(estimated shock velocity of 608 km/s), as well
as a slow, faint, asymmetrical, full-halo CME
visible in coronagraph imagery. The estimated
plane-of-sky speed for the CME was around 430-480
km/s. No proton events were observed at
geosynchronous orbit.
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STEREO B Shock/MC A- Nothing
B- SEP A- Nothing
26 April
29 April
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989 988 987
(992)
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(No Transcript)
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AR Evolution Carr. Rotations 2064 2071 Nov.,
2007 July 2008
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(No Transcript)
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(No Transcript)
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(No Transcript)
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WG4 Science Goals

• Overarching Goal
• Trace the effects of solar structure and activity
  through the solar wind to the Earth, other
  planets spacecraft
• Projects
• Origins/Initiation of CMEs (incl. Active
  regions/Filaments/Prominences)
• Use multi-spectral data and over large distances
  (from Sun)
• Study of specific events
• - March 25 - classic limb CME (WL obs. incl.
  HIs, radio type II, wave)
• - April 9 limb CME w/ EP current sheet
  (WL, spectral, Hinode XRT)
• - Post-CME current sheet evolution
• - Post WHI April 26-29 CME Sun STEREO-B
  connection event
• small SEP shock/MC
• - Modeling??
• Connections with HCS (global magnetic field
  structure), CIRs, streamers/slow wind,
  subsurface flows?
• WSM (SC22-23 minimum) vs WHI (before SC23-24
  min.? tilted CS active regions)