Dr. E.J. Zita, The Evergreen State College, Olympia, WA

1. Sun-Earth Connectionspart of a symposium at the Tacoma campus of The Evergreen State College14.Sept.2001 The Sun and the Earth are both getting hotter. What does the Sun’s magnetic activity have to do with it? What are the consequences? We are investigating questions like these in classes and research at Evergreen. Dr. E.J. Zita, The Evergreen State College, Olympia, WA http://192.211.16.13/individuals/zita/home.htm

2. Outline: • Sun radiates Earth • Earth and Sun are warming • Magnetic activity heats the Sun’s atmosphere • Solar magnetism affects the Earth • How do we measure effects on Earth? On Sun? • How do magnetic fields affect the Sun? • How can we predict magnetic storms? • What can we do about it? • Evergreen contributes to understanding the Sun

3. Sun radiates Earth Nuclear fusion  energetic photons  light and heat Hot gas  energetic charged particles  solar wind Diagrams courtesy of NCAR

4. Sun and Earth are warming The Sun gets bigger and hotter as it grows older (billions of years). The Earth is currently warming out of latest ice age (13,000 yrs). Many factors contribute to (long-term) climate changes and (short-term) temperature variations on Earth. Earth’s average temperature (blue) tracks solar activity (red). From Friis-Christensen, E., and K. Lassen, "Length of the solar cycle: An indicator of solar activity closely associated with climate," Science, 254, 698-700, 1991. See http://web.dmi.dk/solar-terrestrial/space_weather/

5. Magnetic activity heats the Sun’s atmosphere Campfire: hot inside, cooler as you move away Sun: Hot inside, cool surface, but hotter as you move away! Diagrams courtesy of

6. Solar magnetism affects the Earth • Magnetic field lines snap  release hot ions • aurorae: solar ions trapped in Earth’s magnetic field • magnetic storms  power and satellite outages Movies courtesy of

7. How do we measure effects on Earth? http://mlso.hao.ucar.edu/ Solar observatories: Measure luminosity, count sunspots Weather stations: Earth temperatures, atmospheric effects Diagram courtesy of NCAR

8. How do we measure effects on the Sun? TRACE: measures fine-scale solar magnetic fields http://vestige.lmsal.com/TRACE/Project/Mission/mission.htm SOHO: Solar and Heliospheric Observatory: coronal spectrahttp://nssdc.gsfc.nasa.gov/nmc/tmp/1995-065A.html YOHKOH: (Japanese for sunbeam) measures high-energy radiation from solar flares (X-rays and neutrons) and quiet structures and pre-flare conditions. http://nssdc.gsfc.nasa.gov/nmc/tmp/1991-062A.html http://www.solar.isas.ac.jp/english/yohkoh_background2.html

9. Figure 4 Gregory, p.220 How do magnetic fields affect the Sun? Magnetic field lines rise from inside sun  sunspots Twisted field lines  increased magnetic energy Magnetic reconnection  release particles and kinetic energy Magnetic waves  heating Diagram courtesy of Gregory, Stephen A., and Michael Zeilik. Introductory Astronomy and Astrophysics.

10. Magnetic waves in Sun’s atmosphere Research by Evergreen students at NCAR, Boulder Sara Petty-Powell and Matt Johnson Created with 3D MHD code by Rosenthal et al., Oslo

11. Figure 9 Dooling, p. 2 (Dooling, Dave. p. 2) How can we predict magnetic storms? Twisting magnetic fields  s-shaped filaments on photosphere  field lines snap and reconnect  energy release Diagrams courtesy of Montana State University and NCAR

12. Waves in twisted magnetic fields Research by Evergreen faculty at NCAR, Boulder E.J. Zita with Tom Bogdan and B.C. Low Diagrams courtesy of Montana State University

13. What can we do about it? • Not a darn thing? the Sun does what it will • prevention: redesign power circuits and satellites • understand the Sun better:predict magnetic storms and protect satellites • enjoy the increased warmth and aurorae

14. Evergreen contributes understanding Observations theory analysis modeling Theory: Zita calculates magnetic waves in Sun’s atmosphere Modeling: colleagues in Oslo solve equations with computers to generate numerical data (Rosenthal et al.) Observations: colleagues at NCAR and elsewhere observe Sun with satellites to get real data (Lites et al.) Analysis: Students help us understand how numerical data connects to theory and real data (Bogdan et al.)

15. Summary Solar magnetic activity  greater energy from Sun  greater temperatures, aurorae, magnetic storms on Earth Multifacted collaboration  better understanding of Sun and Earth Diagram courtesy of HAO and WET

16. Selected references GONG & NOAO = Global Oscillation Network Group http://www.gong.noao.edu/gonghome.html, http://helios.tuc.noao.edu/ NCAR = National Center for Atmospheric Research, Boulder, CO http://www.hao.ucar.edu/public/education/slides/slides.html MSU = Montana State University http://solar.physics.montana.edu Stanford Solar Center http://solar-center.stanford.edu SOHO: http://sohowww.nascom.nasa.gov/ Kaler, James B. Stars . New York: Scientific American Library, 1992. http://fusedweb.pppl.gov/CPEP/Chart_Pages/5.Plasmas/SunLayers.html#Bib NASA: http://hesperia.gsfc.nasa.gov/sftheory/index.htm Institute for Physics and Astronomy, Aarhus University, Denmark http://www.obs.aau.dk/helio_outreach/ Waves in the magnetic solar atmosphere I, Colin Rosenthal and Tom Bogdan, Astrophysical Journal, 2001 Energy transport by waves above the photosphere, Sara Petty-Powell and Matt Johnson, 2001 Wave transformations in a sheared, force-free magnetic field, E.J. Zita, 2001 http://192.211.16.13/individuals/zita/research.htm