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Physics of the Weird Solar Minimum: New observations of the Sun. Dr. E.J. Zita The Evergreen St. College Olympia WA 98505 [email protected] Abstract.
While solar physicists expected more sunspots, flares, and coronal mass ejections by now, the Sun has defied most predictions by persisting in a relatively quiet state for an unusually long time. Can we tell whether this solar minimum is likely to ease in the next decade, or if it may become a Maunder-type minimum? What evidence is there for mechanisms that might explain the observed delayed and low-amplitude magnetic activity? What effects could decreased solar activity have on Earth\'s climate? Evergreen undergraduates study the Sun with colleagues who built the new Solar Dynamics Observatory (SDO). Students analyzed flows vs. magnetic field tilts; analyzed waves of UV light in active regions; developed a software suite to enable the public to engage with solar dynamics; and cataloged movies of solar events for public release. We use data from the high-resolution HINODE satellite and from the new full-disk SDO. Zita studied the solar dynamo, and found that resistivity gradients can drive magnetic advection. We summarize our work and the light it may shed on questions such as those above.
Shearing of poloidal fields by differential rotation to produce new toroidal fields, followed by eruption of sunspots.
Spot-decay and spreading to produce new surface global poloidal fields.
Transport of poloidal fields by meridional circulation (conveyor belt) toward the pole and down to the bottom, followed by regeneration of new toroidal fields of opposite sign.
Courtesy of Dr. Mausumi Dikpati
Contours: toroidal fields at CZ base Gray-shades: surface radial fields
Observed NSO map of longitude-averaged photospheric fields
Dikpati, de Toma, Gilman, Arge & White, 2004, ApJ, 601, 1136
Solar Dynamics Observatory (SDO):
AIA= Atmospheric Imaging Assembly (12 l, 1 arcsec, 10 sec)
HMI = Helioseismic & Magnetic Imager (continuum, doppler, LOS&vector magnetograms)
EVE = Extreme EUV Expt
D1.00006: Waves and oscillations in the solar atmosphereChristopher Ballou , Mark Cheung , E.J. Zita , Christina Smith
D1.00005: Solar Plasma Flows and Convection in Oblique Magnetic Fields: Christina Smith, E.J. Zita, Neal Hurlburt
Talk at 3:56 in Science 142: H2.00006 : Solar Tutorial and Annotation Resource (STAR): Clay Showalter
Poster D1.00004: Sharing new data from Solar Dynamics Observatory: Benji Friedman
We gratefully acknowledge the use of Mausumi Dikpati\'s kinematic dynamo model, and guidance from Dr. Dikpati and Dr. Peter Gilman (HAO/NCAR, Boulder, CO 80301).We thank Dr. Neal Hurlburt and colleagues at Lockheed Martin Solar and Astrophysics Laboratory for providing guidance and facilities for recent research (Palo Alto, CA 94304), and Dr. Phil Scherrer for sponsoring Evergreen students at Stanford’s Summer Research College.
This work was partially supported by NASA grants NNH05AB521, NNH06AD51I and the NCAR Director\'s opportunity fund; NSF grant 0807651, the Visitor Program of the High Altitude Observatory (HAO) at NCAR, and The Evergreen State College\'s Sponsored Research program.
The National Center for Atmospheric Research (NCAR) is sponsored by the National Science Foundation (NSF). LMSAL is partly supported by NASA.