Speaker
Description
Among the most extreme types of solar energetic particle (SEP) events are those that have hard enough particle spectra to penetrate the Earth’s atmosphere, interact, and cause sufficient secondary particles to be measured by ground-based instrumentation; they are commonly referred to as ‘ground level enhancement’ (GLE) events. By their very definition, GLE events cannot be identified with only space-based instrumentation or at locations far from Earth, yet as we send instrumentation to distant locations with increasing frequency, our need to understand the creation of such strong SEP events and predict them throughout the heliosphere rises.
Solar cycle 24 has had a surprising dearth of GLE events (2 versus the 16 in cycle 23). However, there have been several extreme SEP events observed by STEREO that likely would have been classified as GLE events had they been directed towards Earth. We present an overview of the two cycle 24 GLE events (concentrating on the most recent September 2017 event), along with detailed analysis of the ‘GLE-wannabe’ events observed by the STEREO spacecraft. Detailed solar wind and coronal mass ejection modeling during these events will also be discussed, which may provide some insight into the generation of these extreme events.
