Active Region Nesting, Flux Emergence Patterns, and the Solar Dynamo
Activity nests, also known as active longitudes, are locations where active regions repeatedly emerge over a period of months or years. In addition to commonly hosting flares and/or CMEs, activity nests are interesting because they inform us about the non-axisymmetric nature of the solar dynamo. We report on nesting observed during Solar Cycle 24 and the start of Cycle 25 as studied using HMI/SDO synoptic magnetic maps. Wavelet analysis shows bursty behavior of solar activity that is antisymmetric across the equator, meaning the North and South hemispheres alternate times of increased activity. We search the data for flux emergence patterns with pro and retro-grade rotation rates that may match those of inertial modes or giant cells.
Aimee Norton received her PhD from UCLA where Roger Ulrich served as her thesis adviser. Her thesis focused on using magnetogram data from the MDI instrument on SOHO searching for signatures of MHD waves in the solar photosphere. She worked at the Institute of Astrophysics in the Canary Islands for a summer becoming familiar with vector magnetic field inversion techniques before having postdoctoral positions at Stanford University and HAO. She held tenure track positions at the National Solar Observatory in Tucson, Arizona and James Cook University in Townsville, Australia before she moved back to Stanford to work with the HMI/SDO team. She served as science editor for the Astrophysical Journal from 2017 - 2020. In her free time, she likes to run and read and write poetry.