Letter to the Editor

Recurrent ³He-rich solar energetic particle injections observed by Solar Orbiter at ∼0.5 au^⋆

¹ Southwest Research Institute, 6220 Culebra Rd, San Antonio, TX 78238, USA
e-mail: radoslav.bucik@swri.org
² Applied Physics Laboratory, Johns Hopkins University, 11100 Johns Hopkins Rd, Laurel, MD 20723, USA
³ Lockheed Martin Advanced Technology Center, 3251 Hanover Street, Palo Alto, CA 94304, USA
⁴ Heliophysics Science Division, NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771, USA
⁵ Goddard Planetary Heliophysics Institute, University of Maryland, Baltimore, MD 21250, USA
⁶ Solar-Terrestrial Center of Excellence-SIDC, Royal Observatory of Belgium, Ringlaan -3- Av. Circulaire, 1180 Brussels, Belgium
⁷ The University of Texas at San Antonio, San Antonio, TX 78249, USA
⁸ Universidad de Alcalá, Space Research Group, 28805 Alcalá de Henares, Spain
⁹ Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Leibnizstr. 11, 24118 Kiel, Germany

Received: 9 January 2023
Accepted: 11 April 2023

Abstract

We report Solar Orbiter observations of six recurrent solar energetic particle injections in 2022 March 3−6 at ∼0.5 au. All but one were associated with jets emanating from a plage near a large sunspot in active region 12 957. We saw large jets in injections with high ³He and Fe enrichments and minor jets in injections with no or lower enrichments. Furthermore, the event with the highest enrichment showed a more compact configuration of the underlying photospheric magnetic field. The higher fluences as well as harder spectra were seen in the event with a simultaneous jet and wider eruption. However, in this case, the energy buildup time in the source might be required to produce such spectra. Extreme-ultraviolet images from Solar Orbiter revealed a number of intersecting loops at the base of jets not seen from 1 au that might be a precondition for the recurrent events.