the recent solar minimum how unprecedent is the sun's behavior? andrea opitz cesr (cnrs-ups)...
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The recent solar minimumHow unprecedent is the Sun's behavior?
Andrea OpitzCESR (CNRS-UPS)
University of Toulouse, France
University of Bern, 17th November 2010
Solar activity cycles
David Hathaway, NASA Marshall Space Flight Center
Few hundred years of sunspot record available
Space Age (1960's - today): just a few solar cycles, low statistics
STEREO PLASTIC
SW bulk velocity
SW temperature
SW density
Group:P. Bochsler, P. Wurz, R. Karrer, A. Opitz, L. Blush, H. Daoudi, J. Fischer, M. Sigrist et al. (UoBe)A. B. Galvin, L. Kistler et al. (UNH)
Temporal evolution of the solar wind
PLASTIC proton velocity
0.5 day: ~0.95
2 days: ~0.85
SWEA electron density 0.5 day: ~0.80
2 days: ~0.65
Opitz et al. 2009, Solar Physics
Opitz et al. 2010, Solar Physics
STA STB
STA STB
SWEA
Riley, Luhmann, Opitz, Linker, and Mikic 2010 JGR
Temporal evolution by cross-correlation
STA STB
timelag of ~6 days
Recent Sun and solar wind observations: Facts
• longer solar activity minimum
• solar magnetic field weaker
• coronal holes at low latitudes
• recurrent stream structure broader
• low solar wind densities
• total solar irradiance lower
Terrestrial response 1
• Quiet solar minimum, though geoeffective.
• Interaction of the strong, broad stream structures with the terrestrial magnetosphere.
• Proof: sunspot number alone can not give a good prediction.
Terrestrial response 2
• Opportunity to separate the climatic effects of solar and anthropogenic sources.– Total solar irradiance lower.– Spectral solar irradiance: UV lower, visible
higher.
• Maunder and Dalton minimums
Solar eruption risks
• telegraph system collapsed in 1859• electric network collapsed in 1989
• electric, oil and gas network• satellites: GPS, communication and scientific• pilots and astronauts• radio communication
Summary
• longer solar activity minimum
• solar magnetic field weaker
• coronal holes at low latitudes
• recurrent stream structure broader
• low solar wind densities
• total solar irradiance lower
Questions to the audience
• How much does such an unprecedent solar behavior influence your work?– Climatology?– Planetology?– Cosmic rays?– Space instrumentation?– Solar and Stellar Physics?
Dr. Andrea OPITZ, CESR (CNRS-UPS), University of Toulouse, France