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Statistical Study and Live Catalog of Multispacecraft $^3$He-rich Time Periods over Solar Cycles 23, 24, and 25
| Author | Hart, S.~T.; Dayeh, M.~A.; ik, Bu\vc\; Desai, M.~I.; Ebert, R.~W.; Ho, G.~C.; Li, G.; Mason, G.~M.; |
| Keywords | Parker Data Used; Active sun; Solar energetic particles; Active Solar Corona; Solar atmosphere; Solar abundances; Heliosphere; Solar observatories; 18; 1491; 1988; 1477; 1474; 711; 1513; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
| Abstract | Using ion measurements from Ultra-Low-Energy Isotope Spectrometer observations on board Advanced Composition Explorer and Solar Isotope Spectrometer observations on board the Solar Terrestrial Observatory (STEREO)-A and STEREO-B spacecraft, we have identified 854 $^3$He-rich time periods between 1997 September and 2021 March. We include all event types with observed $^3$He enhancements such as corotating interaction regions, gradual solar energetic particle (SEP) events, interplanetary shocks, and impulsive SEP events. We employ two different mass separation techniques to obtain $^3$He, $^4$He, Fe, and O fluences for each event, and we determine the $^3$He/$^4$He and Fe/O abundance ratios between 0.32-0.45 and 0.64-1.28 MeV nucleon$^-1$. We find a clear correlation in the $^3$He/$^4$He and Fe/O abundance ratios between both energy ranges. We find two distinct trends in the $^3$He/$^4$He versus Fe/O relation. For low $^3$He/$^4$He values, there is a positive linear correlation between $^3$He/$^4$He and Fe/O. However, at $^3$He/$^4$He \raisebox-0.5ex\textasciitilde 0.3, Fe/O appears to reach a limit and the correlation weakens significantly. We provide a live catalog of $^3$He-rich time periods that includes the robust determination of the onset and end times of the $^3$He enhancements in SEP-associated periods for different types of events observed by multiple spacecraft. This catalog is available for public use. New releases will follow after major additions such as adding new periods from new missions (e.g., Parker Solar Probe and Solar Orbiter), identifying event types (impulsive SEP events, etc.), or adding new parameters such as remote observations detailing characteristics of the events active regions. |
| Year of Publication | 2022 |
| Journal | \apjs |
| Volume | 263 |
| Number of Pages | 22 |
| Section | |
| Date Published | dec |
| ISBN | |
| URL | |
| DOI | 10.3847/1538-4365/ac91c1 |
