HR: 1340h
AN: SH13A-1112    [Abstracts]
TI: Preliminary Results of a Study of Rotating Sunspots in Active Regions Utilizing SOHO/MDI Magnetograms During the Solar Maximum in Cycle 23
AU: * Nightingale, R W
EM: nightingale@lmsal.com
AF: Lockheed Martin Adv. Technology Center, Orgn. ADBS, Bldg. 252, 3251 Hanover Street, Palo Alto, CA 94304, United States
AU: Ji, A P
EM: nightingale@lmsal.com
AF: Lockheed Martin Adv. Technology Center, Orgn. ADBS, Bldg. 252, 3251 Hanover Street, Palo Alto, CA 94304, United States
AU: Mayo, S A
EM: nightingale@lmsal.com
AF: Lockheed Martin Adv. Technology Center, Orgn. ADBS, Bldg. 252, 3251 Hanover Street, Palo Alto, CA 94304, United States
AB: As part of a statistical study of sunspots that rotate about their umbral centers in active regions, we have begun to analyze SOHO/MDI full-disk, synoptic magnetogram movies on a daily basis during solar maximum in cycle 23. We are analyzing these active regions when they are least distorted, within approximately +/- 30 degrees longitude of disk center. Many such active regions containing rotating sunspots have been identified. For example, our preliminary study found such active regions near disk center with one or more rotating sunspots for approximately two-thirds of the days in year 2000. Rotating sunspots result from looking temporally at perpendicular slices of a large, twisted magnetic flux tube penetrating through the photosphere from below the solar surface out into the solar corona. The twisted tube, or loop, carries energy via the Poynting flux density up into the corona, where some or all of the energy may be stored in the non-potentiality of the magnetic field to empower flares and coronal mass ejections. Coupling these findings of the presence of rotating sunspots on a majority of days during solar maximum with those from previous studies showing rotating sunspots associated with almost all of the X-flares since April 1998, and many of the M-flares, suggests that rotating sunspots could be providing much of the energy needed by the multitude of large X-ray flares occurring during the solar maximum period. Preliminary results of this study to date will be presented. This work was supported by NASA under the TRACE contract NAS5-38099.
DE: 7500 SOLAR PHYSICS, ASTROPHYSICS, AND ASTRONOMY
DE: 7519 Flares
DE: 7524 Magnetic fields
DE: 7529 Photosphere
DE: 7536 Solar activity cycle (2162)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting