Solar Energetic Particle Alerts from a Coronagraph

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Thursday, February 16, 2017

In this NASA-led study, we report the concept of using near-real time observations from a coronagraph to provide early warning of a fast coronal mass ejection (CME) and the possible onset of a solar energetic particle (SEP) event. The January 1, 2016, fast CME and its associated SEP event are cited as an example.

Link to Eos.org—Research Spotlights: http://agupubs.onlinelibrary.wiley.com/hub/article/10.1002/2016SW001450/editor-highlight/

Space Weather Jan2017 journal cover image
In the top row, the January 1, 2016, eruptive event appears in the sequence of images from SDO AIA [gold], MLSO K-Cor [blue], and SOHO LASCO [red]. A fast coronal mass ejection that was associated with a solar energetic particle event detected near Earth is seen appearing off the southwest limb of the Sun. The ground-based K-Cor coronagraph can provide a timely warning for this particle event, described by St. Cyr, Posner, and Burkepile [Space Weather, 15, doi:10.1002/2016SW001545]. Image credit: Don Kolinski and Joan Burkepile, HAO/NCAR.

The January 1, 2016 CME was detected by the NCAR/HAO groundbased K-Cor coronagraph on Mauna Loa in Hawaii and by SOHO LASCO. The near-real-time availability of the high cadence K-Cor observations in the low corona leads to an obvious question: “Why has no one attempted to use a coronagraph as an early warning device for SEP events?” The answer is that the low image cadence and the long latency of existing spaceborne coronagraphs makes them valid for archival studies but typically unsuitable for near-real-time forecasting. The January 2016 event provided favorable CME viewing geometry and demonstrated that the primary component of a prototype groundbased system for SEP alerts is available several hours on most days. A comparison with other existing techniques shows that a significant temporal advantage for forecasting a SEP onset can be achieved when realtime CME alerts from low coronagraph observations are used in conjunction with other early warning alerts and observations (e.g. X-ray and radio). We discuss how a conceptual CME-based warning system relates to other techniques, including an estimate of the relative SEP alert times, and how such a system might be realized.

Authors: O.C. St.Cyr, NASA-GSFC, A. Posner, NASA-HQ, J.T. Burkepile, HAO/NCAR In this NASA-led study, we report the concept of using near-real time observations from a coronagraph to provide early warning of a fast coronal mass ejection (CME) and the possible onset of a solar energetic particle (SEP) event. The January 1, 2016, fast CME and its associated SEP event are cited as an example.

This paper has been noted by AAAS's EurekAlert! and space.com.

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