Louisiana State University

The Highest Energy Phenomena on the Sun

"The Highest Energy Phenomena on the Sun," colloquium with James Ryan, professor, Department of Physics and Astronomy, University of New Hampshire.

Two superficially related solar phenomena are the subject of some controversy within the solar and heliophysics community. Historically, the first registered or discovered is the Ground Level Enhancement. These were observed as early as the 1940s and are rate increases in neutron monitor or muon detectors, and are associated with major solar activity. They are attributed to hadronic cosmic rays emitted by the Sun in excess of 1 GeV. The other was first observed in 1982, and is called a Long Duration Gamma Ray Flare and is characterized as extended solar gamma ray emission, also in excess of 1 GeV, again associated with major solar activity. Both phenomena exhibit clear evidence of relativistic ions and both emissions are delayed by as much as ten minutes from the solar x-ray flash from the associated solar flare. Similarly, both are prolonged phenomena. Consequently, one tries to draw a direct physical connection between the two. Dr. Ryan will review the various observations that establish these phenomena, and the observational and theoretical failures to link them and how they can be reconciled.

Thursday, November 7, 2019 at 3:30pm to 4:30pm

Nicholson Hall, 119

Event Type

Lectures & Presentations

Target Audience

Students, Faculty, Staff





College of Science, Department of Physics & Astronomy


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