Trends Of The Void: Solar Cycles Observed Through Polar Coronal Holes
Abstract
Coronal holes are defined by their open magnetic field configuration and lack of emitting plasma. Holes that cap the northern and southern solar poles are the longest-lived features observed on the Sun - persisting for nearly an entire solar cycle. Polar holes disappear briefly at solar maximum for about a year before returning. The size and evolution of the polar holes are also strongly anti-correlated with the solar activity cycle. Their longevity combined with this solar activity relationship makes polar coronal holes an ideal proxy for measuring the long-term evolution of the solar magnetic field. We use a perimeter tracking technique to measure the size and location of the polar coronal holes for 19 years starting in 1996. Utilizing the SOHO EIT archive and current SDO AIA images, we present a comprehensive look at how polar coronal holes evolve and what they can tell us about our current and unusual solar cycle.
- Publication:
-
AAS/AGU Triennial Earth-Sun Summit
- Pub Date:
- April 2015
- Bibcode:
- 2015TESS....130802K