Deciphering Solar Magnetic Activity. II. The Solar Cycle Clock and the Onset of Solar Minimum Conditions
| dc.contributor.author | Leamon, Robert | |
| dc.contributor.author | McIntosh, Scott | |
| dc.contributor.author | Chapman, Sandra | |
| dc.contributor.author | Watkins, Nicholas | |
| dc.contributor.author | Chatterjee, Subhamoy | |
| dc.contributor.author | Title, Alan | |
| dc.date.accessioned | 2021-02-05T17:05:35Z | |
| dc.date.available | 2021-02-05T17:05:35Z | |
| dc.description.abstract | The Sun's variability is controlled by the progression and interaction of the magnetized systems that form the 22-year magnetic activity cycle (the "Hale Cycle") as they march from their origin at ∼55 degrees latitude to the equator, over ∼19 years. We will discuss the end point of that progression, dubbed "terminator" events, and our means of diagnosing them. Based on the terminations of Hale Magnetic Cycles, we construct a new solar activity "clock" which maps all solar magnetic activity onto a single normalized epoch. The Terminators appear at phase 0∗2π on this clock (by definition), then solar polar field reversals commence at 0.2∗2π, and the geomagnetically quiet intervals centered around solar minimum, start at 0.6∗2π and end at the terminator, lasting 40% of the normalized cycle length. With this onset of quiescence, dubbed a "pre-terminator," the Sun shows a radical reduction in active region complexity and (like the terminator events) is associated with the time when the solar radio flux crosses F10.7=90 sfu -- effectively marking the commencement of solar minimum conditions. In this paper we use the terminator-based clock to illustrate a range of phenomena associated with the pre-terminator "event" that further emphasize the strong interaction of the global-scale magnetic systems of the Hale Cycle. | en_US |
| dc.description.sponsorship | This material is based upon work supported by the National Center for Atmospheric Research, which is a major facility sponsored by the National Science Foundation under Cooperative Agreement No. 1852977. RJL acknowledges support from NASA’s Living With a Star Program. We thank Phil Scherrer and J. Todd Hoeksema for their assistance with, and discussions on, the Wilcox Solar Observatory data, and Dipankar Bannerjee for assistance with the Kodaikanal Observatory data. | en_US |
| dc.description.uri | https://arxiv.org/abs/2012.15186 | en_US |
| dc.format.extent | 27 pages | en_US |
| dc.genre | journal articles preprints | en_US |
| dc.identifier | doi:10.13016/m2r4ti-g532 | |
| dc.identifier.citation | Robert Leamon, Scott McIntosh, Sandra Chapman, Nicholas Watkins, Subhamoy Chatterjee and Alan Title, Deciphering Solar Magnetic Activity. II. The Solar Cycle Clock and the Onset of Solar Minimum Conditions, https://arxiv.org/abs/2012.15186 | en_US |
| dc.identifier.uri | http://hdl.handle.net/11603/20947 | |
| dc.language.iso | en_US | en_US |
| dc.relation.isAvailableAt | The University of Maryland, Baltimore County (UMBC) | |
| dc.relation.ispartof | UMBC Goddard Planetary Heliophysics Institute (GPHI) | |
| dc.relation.ispartof | UMBC Faculty Collection | |
| dc.rights | This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author. | |
| dc.rights | Attribution 4.0 International | * |
| dc.rights.uri | https://creativecommons.org/licenses/by/4.0/ | * |
| dc.title | Deciphering Solar Magnetic Activity. II. The Solar Cycle Clock and the Onset of Solar Minimum Conditions | en_US |
| dc.type | Text | en_US |