How much more can sunspots tell us about the solar dynamo?
Paper
Paper/Presentation Title | How much more can sunspots tell us about the solar dynamo? |
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Presentation Type | Paper |
Authors | Norton, Aimee A. (Author), Jones, Eric H. (Author), Liu, Y. (Author), Hayashi, K. (Author), Hoeksema, J. T. (Author) and Schou, Jesper (Author) |
Editors | Kosovichev, A. G., de Gouveia Dal Pino, E. and Yan, Y. |
Journal or Proceedings Title | Proceedings of the International Astronomical Union |
ERA Conference ID | 50528 |
Journal Citation | 8 (S294), pp. 25-36 |
Number of Pages | 12 |
Year | 2012 |
Publisher | Cambridge University Press |
Place of Publication | Cambridge, United Kingdom |
ISSN | 1743-9213 |
1743-9221 | |
ISBN | 9781107033832 |
Digital Object Identifier (DOI) | https://doi.org/10.1017/S1743921313002172 |
Conference/Event | 28th International Astronomical Union Symposium (IAU 2012): Solar and Astrophysical Dynamos and Magnetic Activity |
International Astronomical Union Symposium | |
Event Details | 28th International Astronomical Union Symposium (IAU 2012): Solar and Astrophysical Dynamos and Magnetic Activity Event Date 27 to end of 31 Aug 2012 Event Location Beijing, China |
Event Details | International Astronomical Union Symposium IAU Symposium |
Abstract | Sunspot observations inspired solar dynamo theory and continue to do so. Simply counting them established the sunspot cycle and its period. Latitudinal distributions introduced the tough constraint that the source of sunspots moves equator-ward as the cycle progresses. Observations of Hale's polarity law mandated hemispheric asymmetry. How much more can sunspots tell us about the solar dynamo? We draw attention to a few outstanding questions raised by inherent sunspot properties. Namely, how to explain sunspot rotation rates, the incoherence of follower spots, the longitudinal spacing of sunspot groups, and brightness trends within a given sunspot cycle. After reviewing the first several topics, we then present new results on the brightness of sunspots in Cycle 24 as observed with the Helioseismic Magnetic Imager (HMI). We compare these results to the sunspot brightness observed in Cycle 23 with the Michelson Doppler Imager (MDI). Next, we compare the minimum intensities of five sunspots simultaneously observed by the Hinode Solar Optical Telescope Spectropolarimeter (SOT-SP) and HMI to verify that the minimum brightness of sunspot umbrae correlates well to the maximum field strength. We then examine 90 and 52 sunspots in the north and south hemisphere, respectively, from 2010 - 2012. Finally, we conclude that the average maximum field strengths of umbra 40 Carrington Rotations into Cycle 24 are 2690 Gauss, virtually indistinguishable from the 2660 Gauss value observed at a similar time in Cycle 23 with MDI. |
Keywords | dynamo; magnetic fields; sunspots |
ANZSRC Field of Research 2020 | 400909. Photonic and electro-optical devices, sensors and systems (excl. communications) |
510402. Condensed matter imaging | |
519999. Other physical sciences not elsewhere classified | |
Public Notes | © International Astronomical Union 2013. |
Byline Affiliations | Stanford University, United States |
Centre for Astronomy and Atmospheric Research | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q2048/how-much-more-can-sunspots-tell-us-about-the-solar-dynamo
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