Related papers: Unusual Circumstances of the 2024 June 8 GLE
The sustained gamma ray emission (SGRE) from the Sun is one of the fascinating high energy phenomena closely related to the acceleration of protons to energies >300 MeV. Here we report on the solar cycle variation of SGRE events based on…
We report on the source of greater than 300 MeV protons during the SOL2014-09-01 sustained gamma-ray emission (SGRE) event based on multi-wavelength data from a wide array of space- and ground-based instruments. Based on the eruption…
The sustained gamma-ray emission (SGRE) events from the Sun are associated with an ultrafast (2000 km/s or greater) halo coronal mass ejection (CME) and a type II radio burst in the decameter-hectometric (DH) wavelengths. The SGRE duration…
We characterize and provide a catalog of thirty >100 MeV sustained gamma-ray emission (SGRE) events observed by Fermi LAT. These events are temporally and spectrally distinct from the associated solar flares. Their spectra are consistent…
We report that the number of > 500 MeV protons (Ng) inferred from sustained gamma ray emission (SGRE) from the Sun is significantly correlated with that of protons propagating into space (NSEP) as solar energetic particles (SEPs). Under the…
The Sun is already in the declining phase of cycle 24, but the paucity of high-energy solar energetic particle (SEP) events continues with only two ground level enhancement (GLE) events as of March 31, 2015. In an attempt to understand…
We report on the 2024 September 9 sustained gamma ray emission (SGRE) event observed by the Large Area Telescope (LAT) onboard the Fermi satellite. The event was associated with a backside solar eruption observed by multiple spacecraft such…
We report on the linear relationship between the durations of two types of electromagnetic emissions associated with shocks driven by coronal mass ejections: sustained gamma-ray emission (SGRE) and interplanetary type II radio bursts. The…
High energy solar protons were observed by particle detectors aboard spacecraft in near-Earth orbit on May 11, 2024 and produced the 74th ground level enhancement (GLE74) event registered by ground-based neutron monitors. This study…
We present a study of the 2014 January 6 solar energetic particle (SEP) event, which produced a small ground level enhancement (GLE), making it the second GLE of this unusual solar cycle 24. This event was primarily observed by the South…
Large solar eruptive events, including solar flares and coronal mass ejections (CMEs), can lead to solar energetic particle (SEP) events. During these events, protons are accelerated up to several GeV and pose numerous space weather risks.…
We report on a study of all major solar eruptions that occurred on the front-side of the Sun during the rise to peak phase of cycle 24 (first 62 months) in order to understand the key factors affecting the occurrence of large solar…
We present an overview of the observed properties of the GLEs and those of the associated flares and CMEs. The solar eruptions are very intense involving X-class flares and extreme CME speeds (average ~2000 km/s). The active regions in…
In addition to several recent articles devoted to the rare event of ground-level enhancement of the solar relativistic proton flux observed on 2021 October 28 (GLE73), we study the 10-100 MeV solar energetic particle (SEP) component of this…
It has recently been shown that the spatially and temporally extended gamma-ray emission in solar eruptions are caused by greater than 300 MeV protons precipitating on the Sun from shocks driven by coronal mass ejections (CMEs). The…
We report on the close similarity of coronal mass ejection (CME) properties in ground level enhancement (GLE) in solar energetic particle (SEP) events and sustained gamma ray emission (SGRE) from the Sun as indicated by low frequency type…
{\sl Ground Level Enhancement (GLE)} events represent the largest class of {\sl solar energetic particle (SEP)} events that require acceleration processes to produce $\gapprox 1$ GeV ions in order to produce showers of secondary particles…
We report on the 2017 September 10 ground level enhancement (GLE) event associated with a coronal mass ejection (CME) whose initial acceleration (~9.1km s^-2) and initial speed (~4300 km/s) were among the highest observed in the SOHO era.…
We present a multi-spacecraft analysis of the 2024 July 16 Long-Duration Gamma-Ray Flare (LDGRF) detected by the Large Area Telescope on the Fermi satellite. The measured >100 MeV $\gamma$-ray emission persisted for over seven hours after…
Ground level events (GLEs) occupy the high-energy end of gradual solar energetic particle (SEP) events. They are associated with coronal mass ejections (CMEs) and solar flares, but we still do not clearly understand the special conditions…