FORecasting Solar Particle Events and Flares


The FORecasting Solar Energetic Particles and Flares (FORSPEF) tool provides forecasting of solar eruptive events, such as solar flares (SF) with a projection to coronal mass ejections (CMEs) (occurrence and velocity) and the likelihood of occurrence of a solar energetic proton (SEP) event. It also provides nowcasting of SEP events based on actual SF and CME near real-time alerts, as well as nowcasting of SEP characteristics (peak flux, fluence, rise time, duration) per parent solar event.

For the implementation of the forecasting system of SF, a novel method was developed based upon the effective connected magnetic field strength (Beff) metric and it utilizes analysis of a large number of active region (AR) magnetograms (see M. K. Georgoulis & D. M. Rust, Astrophys. J. , 2007, 661, L109). For a given AR, under the condition of a specific calculated Beff value, the system implemented under FORSPEF, derives conditional-probabilities for SF of all sizes (C1.0 - X10), the respective CME-likelihood for each flare class, as well as, a projected near-Sun CME velocity relying on the given Beff value independently inferred. For the implementation of the forecasting system of SEP events, a new database was developed, covering a large time-span (~30 years) and, for the first time, the statistics were built from recently re-calibrated GOES proton data (see I. Sandberg et al., GRL, 2014, vol 41, Issue 13, pp 4435-4441). For a given Solar flare with known characteristics (e.g. maximum flare flux, position), the algorithm provides probabilities of SEP occurrence, in the forecasting pre-flare mode, and on top of this, SEP expected characteristics (e.g. peak time, peak flux, duration) in the nowcasting post-flare mode. In addition, for a given CME with known characteristics (e.g. velocity, width), the algorithm further provides probabilities of SEP occurrence as well as SEP expected characteristics (e.g. peak flux and fluence).

Predictions are issued for all > C1.0 soft X-ray flares. The prediction time in the forecasting scheme extends to 24 hours with a refresh rate of 3 hours while the nowcasting mode provides a complete prognosis of SEP events from their probability of occurrence to their expected characteristics (in terms of SEP event's peak flux, peak time), based on near-real time SF data, with a refreshing rate of ~15-20 minutes and on near real-time CME data with a refreshing rate of ~6 hours.

The FORSPEF Tool provides notifications to registered users on the Occurrence and the Expected Characteristics of forthcoming Solar Energetic Particle (SEP) radiation storms, either for a given SF or for a CME, with known characteristics. All notifications are issued when the calculated probability of SEP Occurrence is >=0.25 .

A more detailed description on the FORSPEF tool can be found in (Papaioannou et al., Journal of Physics: Conference Series, 2015, 632 ,012075).