Karel Schrijver

Title: The Sun's Magnetic Activity, Space Weather, and Societal Impacts  (Video)

Abstract: The variable conditions in geospace driven by the Sun’s magnetic activity, known as space weather, pose an increasing threat to society. Poorly known and infrequent extreme space storms are anticipated to have large effects, but statistical evidence shows that even quite common space storms cause significant problems for electric power grids, navigation systems, and satellite-based communications.  All space weather is ultimately powered by the Sun's magnetic dynamo, leading to both the quiescent background solar irradiance and wind, and the impulsive phenomena associated with coronal mass ejections and energetic particle storms.  How do we know about the societal costs of space weather? How can we quantify frequencies of extreme events? How can we know the distant past and future of the climate of geospace? The answers lie in insurance claim records, in radionuclides hidden in ancient rocks and in slow-moving glaciers, in the behavior of thousands of Sun-like stars, and in the combination of nuclear physics and observations of star clusters. In this seminar, I will take you on a tour around the theme of space weather, from causes to impacts, to give you a flavor of the lives of magnetically active stars, including our Sun.