Topical Discussion Meeting - Challenges in Understanding and Predicting Geomagnetic Storms without Clear Signatures on or near the Sun

Nariaki Nitta (Lockheed Martin Advanced Technology Center), Tamitha Mulligan (Aerospace Corporation), Emilia Kilpua (University of Helsinki), Benjamin Lynch (University of California Berkeley), Marilena Mierla (Royal Observatory of Belgium), Jennifer O’kane (University College London), Paolo Pagano (University of St. Andrews), Erika Palmerio (University of Helsinki), Jens Pomoell (University of Helsinki), Ian Richardson (NASA/GSFC and University of Maryland), Luciano Rodriguez (Royal Observatory of Belgium), Alexis Rouillard (University of Toulouse), Nandita Srivastava (Udaipur Solar Observatory), Dana-Camelia Talpeanu (KU Leuven), Stephanie Yardley (University of St. Andrews), Andrei Zhukov (Royal Observatory of Belgium)
Monday 5/11, 17:15-18:30
MTC 00.10, Large lecture room

Space weather is not just about possible Carrington-class events, but not-so-extreme events that occur more frequently can also have significant societal impacts. Some of them, even with reasonably clear signatures of interplanetary coronal mass ejections (ICMEs), may not be traced back to a coronal mass ejection (CME) near the Sun, and even if the CME is identified its origin may be elusive in coronal images. This results in big uncertainties in estimating the magnetic field structure that is responsible for the observed ICME. These “stealthy” events tend to occur close to open field regions, and their weak manifestations in in situ data may be overwhelmed by high speed streams from coronal holes and their associated stream interaction regions. In this meeting we start with a brief overview of geomagnetic storms and ICMEs in solar cycle 24 whose origins have been searched for but far from unanimously agreed on. We then discuss a solar-cycle dependence of these events. We close our meeting with discussing new observational and modeling approaches that may advance our understanding of the origins and consequences of stealthy solar eruptions with geo-effective potential.

REPORT