Catalogue of 55-80 MeV solar proton events extending through solar cycles 23 and 24

Abstract

We present a new catalogue of solar energetic particle events near the Earth, covering solar cycle 23 and the majority of solar cycle 24 (1996-2016), based on the 55-80 MeV proton intensity data gathered by the SOHO/ERNE experiment. In addition to ERNE proton and heavy ion observations, data from the ACE/EPAM (near-relativistic electrons), SOHO/EPHIN (relativistic electrons), SOHO/LASCO (coronal mass ejections, CMEs), and GOES soft X-ray experiments are also considered and the associations between the particle and CME/X-ray events deduced to obtain a better understanding of each event. A total of 176 SEP events have been identified as having occurred during the time period of interest; their onset and solar release times have been estimated using both velocity dispersion analysis (VDA) and time-shifting analysis (TSA) for protons, as well as TSA for near-relativistic electrons. Additionally, a brief statistical analysis has been performed on the VDA and TSA results, as well as the X-rays and CMEs associated with the proton/electron events, both to test the viability of the VDA and to investigate possible differences between the two solar cycles. We find, in confirmation of a number of previous studies, that VDA results for protons that yield an apparent path length of 1 AU < s <~ 3 AU seem to be useful, but those outside this range are probably unreliable, as evidenced by the anticorrelation between apparent path length and release time estimated from the X-ray activity. It also appears that even the first-arriving energetic protons apparently undergo significant pitch angle scattering in the interplanetary medium, with the resulting apparent path length being on average about twice the length of the spiral magnetic field. The analysis indicates an increase in high-energy SEP events originating from the far eastern solar hemisphere; e.g., such an event...

arXiv comment33 pages, 12 figures (2 with multiple image files), 1 appendix as an external PDF file. Article is in the accepted manuscript/referee (single column) format

References in corpus (5)

• The Two Sources of Solar Energetic Particles
• Relationship between Solar Energetic Particles and Properties of Flares and CMEs: Statistical Analysis of Solar Cycle 23 Events
• Investigation of the Neupert effect in solar flares. I. Statistical properties and the evaporation model
• On the Estimation of Solar Energetic Particle Injection Timing from Onset Times near Earth
• 25 MeV Solar Proton Events in Cycle 24 and Previous Cycles

Cited by in corpus (11)

• Catalogue of >55 MeV Wide-longitude Solar Proton Events Observed by SOHO, ACE, and the STEREOs at $\approx$1 AU during 2009-2016
• From Sun to interplanetary space: What is the pathlength of Solar Energetic Particles?
• The Wind/EPACT proton event catalog (1996-2016)
• High Energy Solar Particle Events and Their Relationship to Associated Flare, CME and GLE Parameters
• Integrated Geostationary Solar Energetic Particle Events Catalog: GSEP
• An analytical model of turbulence in Parker spiral geometry and associated magnetic field line lengths
• The Electron Proton Helium INstrument as an Example for a Space Weather Radiation Instrument
• Solar Energetic Particle event onsets at different heliolongitudes: The effect of turbulence in Parker Spiral Geometry
• New insights from cross-correlation studies between solar activity indices and cosmic-ray flux during Forbush decrease events
• Formation of Isolated Radio Type II Bursts at Low Frequencies
• Revisiting Empirical Solar Energetic Particle Scaling Relations II. Coronal Mass Ejections