How much more can sunspots tell us about the solar dynamo?

Paper


Norton, Aimee A., Jones, Eric H., Liu, Y., Hayashi, K., Hoeksema, J. T. and Schou, Jesper. 2012. "How much more can sunspots tell us about the solar dynamo? " Kosovichev, A. G., de Gouveia Dal Pino, E. and Yan, Y. (ed.) 28th International Astronomical Union Symposium (IAU 2012): Solar and Astrophysical Dynamos and Magnetic Activity. Beijing, China 27 - 31 Aug 2012 Cambridge, United Kingdom. https://doi.org/10.1017/S1743921313002172
Paper/Presentation Title

How much more can sunspots tell us about the solar dynamo?

Presentation TypePaper
AuthorsNorton, Aimee A. (Author), Jones, Eric H. (Author), Liu, Y. (Author), Hayashi, K. (Author), Hoeksema, J. T. (Author) and Schou, Jesper (Author)
EditorsKosovichev, A. G., de Gouveia Dal Pino, E. and Yan, Y.
Journal or Proceedings TitleProceedings of the International Astronomical Union
ERA Conference ID50528
Journal Citation8 (S294), pp. 25-36
Number of Pages12
Year2012
PublisherCambridge University Press
Place of PublicationCambridge, United Kingdom
ISSN1743-9213
1743-9221
ISBN9781107033832
Digital Object Identifier (DOI)https://doi.org/10.1017/S1743921313002172
Conference/Event28th 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.

Keywordsdynamo; magnetic fields; sunspots
ANZSRC Field of Research 2020400909. 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 AffiliationsStanford University, United States
Centre for Astronomy and Atmospheric Research
Institution of OriginUniversity of Southern Queensland
Permalink -

https://research.usq.edu.au/item/q2048/how-much-more-can-sunspots-tell-us-about-the-solar-dynamo

  • 1796
    total views
  • 29
    total downloads
  • 2
    views this month
  • 0
    downloads this month

Export as

Related outputs

Comparison of coronal extrapolation methods for cycle 24 using HMI data
Arden, William, Norton, Aimee, Sun, Xudong and Zhao, Xuepu. 2016. "Comparison of coronal extrapolation methods for cycle 24 using HMI data." The Astrophysical Journal: an international review of astronomy and astronomical physics. 823 (1). https://doi.org/10.3847/0004-637X/823/1/21
A breathing source surface for cycles 23 and 24
Arden, W. M., Norton, A. A. and Sun, X.. 2014. "A breathing source surface for cycles 23 and 24 ." Journal of Geophysical Research: Space Physics. 119 (3), pp. 1476-1485. https://doi.org/10.1002/2013JA019464
Re-examining sunspot tilt angle to include anti-Hale statistics
McClintock, B. H., Norton, A. A. and Li, J.. 2014. "Re-examining sunspot tilt angle to include anti-Hale statistics." The Astrophysical Journal: an international review of astronomy and astronomical physics. 797 (2), pp. 1-10. https://doi.org/10.1088/0004-637X/797/2/130
How do the magnetic field strengths and intensities of sunspots vary over the solar cycle?
Norton, A. A., Jones, E. H. and Liu, Y.. 2013. "How do the magnetic field strengths and intensities of sunspots vary over the solar cycle?" Eclipse on the Coral Sea: Cycle 24 Ascending (2013). Palm Cove, Australia 12 - 16 Nov 2012 Bristol, United Kingdom. https://doi.org/10.1088/1742-6596/440/1/012038