High Energy Solar Particle Events and Their Relationship to Associated Flare, CME and GLE Parameters

• Published in: Space Weather Vol. 21; no. 3
• Main Authors: Waterfall, C. O. G., Dalla, S., Raukunen, O., Heynderickx, D., Jiggens, P., Vainio, R.
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 01.03.2023
• Subjects: Astronauts; Coronal mass ejection; Correlation; Datasets; Electronics; Energetic particles; Energy; Forecasting; GOES satellites; Mathematical models; Mitigation; Parameters; Particle physics; Protons; Radiation; Radiation dosage; Radiation hazards; Satellites; Solar corona; Solar cycle; Solar energy; Solar flares; Solar particle events; Solar storms; Space weather; Spacecraft; Weather
• ISSN: 1542-7390; 1539-4964; 1542-7390
• DOI: 10.1029/2022SW003334

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. These risks include, but are not limited to, radiation hazards to astronauts and disruption to satellites and electronics. The highest energy SEPs are capable of reaching Earth on timescales of minutes and can be detected in ground level enhancements (GLEs). Understanding and analyzing these events is critical to future forecasting models. However, the availability of high energy SEP data sets is limited, especially that which covers multiple solar cycles. The majority of analysis of SEP events considers data at energies <100 MeV. In this work, we use a newly calibrated data set using data from Geostationary Operational Environmental Satellite‐high energy proton and alpha detector between 1984 and 2017. Analysis of the SEP events in this time period over three high energy channels is performed, and SEP properties are compared to flare and CME parameters. In addition, neutron monitor (NM) observations are examined for the relevant GLE events. We find that correlations between SEP peak intensity and the CME speed are much weaker than for lower SEP energies. Correlations with flare intensity are broadly similar or weaker. Strong correlations are seen between >300 MeV data and GLE properties from NM data. The results of our work can be utilized in future forecasting models for both high energy SEP and GLE events. Plain Language Summary Large eruptive events on the Sun can produce particles over a range of energies. The highest energy particles are the most hazardous and can quickly spread through space and reach Earth within minutes. The particles can interfere with satellite electronics and cause increased radiation doses to astronauts as well as pilots and flight passengers. Many studies exist of low energy particles, due to the increased number of spacecraft able to observe at these energies. However, the rarer high energy particles pose the most risks and are important to understand more. This study utilizes a new data set from a spacecraft that covers these most hazardous energies. This high energy particle data set is compared to features from the solar eruption, for example, the size of the associated solar flare. Strong relations are found between the high energy particles observed in space and their subsequent detection at ground level. This study can be used to improve forecasts of these events and improve our understanding and mitigation of these hazardous events. Key Points High energy solar energetic particle (SEP) data are analyzed over multiple solar cycles and compared to features of the associated flare, coronal mass ejection (CME) and ground level enhancement Strong correlations are seen between >300 MeV SEP observations and neutron monitor data Correlations between SEP, CME, and flare parameters are weaker than in lower energy analysis