Solar extreme events

Abstract

Solar flares and CMEs have a broad range of magnitudes. This review discusses the possibility of "extreme events," defined as those with magnitudes greater than have been seen in the existing historical record. For most quantitative measures, this direct information does not extend more than a century and a half into the recent past. The magnitude distributions (occurrence frequencies) of solar events (flares/CMEs) typically decrease with the parameter measured or inferred (peak flux, mass, energy etc. Flare radiation fluxes tend to follow a power law slightly flatter than $S^{-2}$, where S represents a peak flux; solar particle events (SPEs) follow a still flatter power law up to a limiting magnitude, and then appear to roll over to a steeper distribution, which may take an exponential form or follow a broken power law. This inference comes from the terrestrial ${}^{14}$C record and from the depth dependence of various radioisotope proxies in the lunar regolith and in meteorites. Recently major new observational results have impacted our use of the relatively limited historical record in new ways: the detection of actual events in the ${}^{14}$C tree-ring records, and the systematic observations of flares and "superflares" by the Kepler spacecraft. I discuss how these new findings may affect our understanding of the distribution function expected for extreme solar events.

24th European Cosmic Ray Symposium, Christian-Albrechts-Universitaet zu Kiel, September 2014

References in corpus (10)

• The Two Sources of Solar Energetic Particles
• Superflares on Solar Type Stars Observed with Kepler I. Statistical Properties of Superflares
• Toward Reliable Benchmarking of Solar Flare Forecasting Methods
• Impulsive and Long Duration High-Energy Gamma-ray Emission From the Very Bright 2012 March 7 Solar Flares
• Superflare occurrence and energies on G-, K- and M-type dwarfs
• Chromospheric and Coronal Observations of Solar Flares with the Helioseismic and Magnetic Imager
• Occurrence Probability of Large Solar Energetic Particle Events: Assessment from Data on Cosmogenic Radionuclides in Lunar Rocks
• The Unpredictability of the Most Energetic Solar Events
• Helioseismic and Magnetic Imager observations of linear polarization from a loop prominence system
• A solar super-flare as cause for the 14C variation in AD 774/5 ?

Cited by in corpus (4)

• Extreme solar events
• Do Kepler superflare stars really include slowly-rotating Sun-like stars ? - Results using APO 3.5m telescope spectroscopic observations and Gaia-DR2 data -
• Physical constraints for the evolution of life on exoplanets
• Multi-waveband detection of quasi-periodic pulsations in a stellar flare on EK Draconis observed by XMM-Newton