Using Polar Coronal Hole Area Measurements to Determine the Solar Polar Magnetic Field Reversal in Solar Cycle 24

Autor:	William Dean Pesnell, S. A. Hess Webber, Nishu Karna
Rok vydání:	2014
Předmět:	Physics Northern Hemisphere Astronomy Coronal hole Astronomy and Astrophysics Coronal loop Solar cycle 24 Corona Geomagnetic reversal Solar cycle Space and Planetary Science Physics::Space Physics Astrophysics::Solar and Stellar Astrophysics Polar Astrophysics::Earth and Planetary Astrophysics
Zdroj:	Solar Physics. 289:3381-3390
ISSN:	1573-093X 0038-0938
Popis:	An analysis of solar polar coronal hole (PCH) areas since the launch of the Solar Dynamics Observatory (SDO) shows how the polar regions have evolved during Solar Cycle 24. We present PCH areas from mid-2010 through 2013 using data from the Atmospheric Imager Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) instruments onboard SDO. Our analysis shows that both the northern and southern PCH areas have decreased significantly in size since 2010. Linear fits to the areas derived from the magnetic-field properties indicate that, although the northern hemisphere went through polar-field reversal and reached solar-maximum conditions in mid-2012, the southern hemisphere had not reached solar-maximum conditions in the polar regions by the end of 2013. Our results show that solar-maximum conditions in each hemisphere, as measured by the area of the polar coronal holes and polar magnetic field, will be offset in time.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::d5cac9bfe0aa617bde6f49213c1b9fd0 https://doi.org/10.1007/s11207-014-0541-7 Zobrazit plný text záznamu Plný text ve formátu PDF