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Solar Sector Structure Correlations with SuperDARN Radar and EISCAT Svalbard Radar Data
Devin Huyghebaert and Kathryn McWilliamsDepartment of Physics and Engineering Physics
University of SaskatchewanJune 1, 2011
Outline
- Introduction - Solar sector structure - Quick overview of previous studies
- SuperDARN Results
- ISR Results
- Future Work
Introduction
(Akasofu, 1981)
- Solar current sheet
- Interplanetary Magnetic Field (IMF) directed one direction above current sheet, and opposite direction below current sheet.
- Earth finds itself above and below current sheet during orbit (Wilcox & Ness, 1967)
“away”
“away”“toward”
“toward”
Introduction
(Fairfield & Scudder, 1985)
- “towards” solar sectors connect southern polar cap upstream
- “away” solar sectors connect northern polar cap upstream
Introduction
- Summary of away/toward solar sectors for 10 years, 1998-2007
- Almost full solar cycle worth of data
Connections to Tropospheric Weather?
(Tinsley, 2000)
- Vorticity Area Index (VAI) - measure of low pressure troughs in Northern Hemisphere at latitudes >20°
- Past studies have shown correlations between solar sector boundary crossings and VAI
- Is there a link?
Past Study – Ionospheric Backscatter
day of month
Past Study – Ionospheric Backscatter
day of month
Results – Saskatoon SuperDARN Groundscatter 2003
-Groundscatter vs. ionospheric backscatter
- More groundscatter in “towards” sectors
- Occurs Distinctly in second half of 2003
- Same trend in ionospheric backscatter
Year
Hou
rly G
roun
dsca
tter
Cou
nt
t t t
a a a
(Gilles, 2006)
Results
t ttta aaat
Results – Saskatoon SuperDARN Groundscatter 2004
- 2004, solar sector structure no longer well defined
- difficult to find any correlation during this period
Year
Hou
rly G
roun
dsca
tter
Cou
nt
Results – SuperDARN Groundscatter 2003
90%
90%
70%
70%
50%50%
30%
30%
10% 10%
at ta
Results – SuperDARN Groundscatter 2004
90%90%
70%70%
50% 50%
30% 30%
10% 10%
t ta a
Results – SuperDARN Ionospheric Scatter 2003
90%
90%
70%
70%
50%
50%
30%
30%
10% 10%
t ta a
Results – Southern SuperDARN Groundscatter 2003
90%
70%50%
30%10%
t a
90%
70%50%
30%
10%
ta
Results – Solar Wind Data
- ACE Data
- 2003 shows an increase in solar wind velocity, and a decrease in solar wind density
SW Velocity
SW Density
Results – Incoherent Scatter Radar
- EISCAT Svalbard Radar (ESR) 42m field-aligned dish
- Opposite Correlations in E- and F- regions
- 27 day repetition of trend
2007 day 60-310
Electron Density
Lag Days
Hei
ght (
km)
Conclusions
- SuperDARN Groundscatter/Ionospheric Backscatter
- count increase in “towards” (southern polar cap connected)
- count decrease in “away” (northern polar cap connected)
- caused by propagation effects
- occurs in 2003, not evident in other years
- only evident in Northern Hemisphere
- often a peak within a day of the boundary crossing
- ISR Electron Density
- E- and F- region 27 day synodic solar rotation evident
Future Work
- Further analyze ISR data
- 2003, solar sector structure was well defined
- 2007, what is happening in the E- and F-regions?
- Analyze other ISR high-latitude locations (Svalbard,
Poker Flat, RISR-N, etc.)
- Link to NO density/D-region ionization?
- DMSP
References
Akasofu, S. -I., Energy coupling between the solar wind and the magnetosphere, Space Science Reviews, 28(2), pp. 121-190, 1981.
Fairfield, D. H., and Scudder, J. D., Polar rain: Solar coronal electrons in the Earth's magnetosphere, J. Geophys. Res., 90, pp. 4055, 1985.
Larsen, M.F., & M.C. Kelley, A study of an observed and forecasted meteorological index and its relation to the interplanetary magnetic field, Geophys. Res. Lett., 4:8, pp. 337-340, 1977.
Tinsley, B.A., Influence of solar wind on the global electric circuit, and inferred effects on cloud microphysics, temperature, and dynamics in the troposphere, Space Science Reviews, 94:1-2, pp.
231-258, 2000.
Tinsley, B. A., and R. A. Heelis, Correlations of atmospheric dynamics with solar activity evidence for a connection via the solar wind, atmospheric electricity, and cloud microphysics, J. Geophys.
Res., 98(D6), pp. 10,375–10,384, 1993.
Wilcox, J.M., Tropospheric circulation and interplanetary magnetic sector boundaries followed by MeV proton streams, Nature, 278, pp. 840-841, 1979.
Wilcox, J.M., and N.F. Ness, Solar source of the interplanetary sector structure, Solar Physics, 1:3-4, pp. 437-P445, 1967.
Results
- Attempted finding F- and E- region heights from groundscatter
- Problem with elevation angle
Results
- E- and F- regions have the same sign correlation
- 27 day repetition of trend
2007 day 60-310
Ion Temperature
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