Suprathermal particles from corotating interaction regions during the first perihelion pass of Solar Orbiter
Robert C. Allen, G. M. Mason, G. C. Ho, J. Rodrı́guez-Pacheco, R. F. Wimmer‐Schweingruber, G. B. Andrews, L. Berger, S. Boden, I. Cernuda, F. Espinosa Lara, J. L. Freiherr von Forstner, R. Gómez‐Herrero, J. R. Hayes, S. R. Kulkarni, W. J. Lees, César Martı́n, D. Pacheco, Óscar R. Polo, Manuel Prieto, A. Ravanbakhsh, Sebastián Sánchez, C. E. Schlemm, H. Seifert, J. C. Terasa, K. Tyagi, Zigong Xu, M. Yedla
Abstract
The first orbit of Solar Orbiter provided comprehensive measurements of six corotating interaction regions (CIRs) within 1 au. Five of these CIRs were also observed by ACE at 1 au, allowing for comparisons of the suprathermal ion intensities and spectra at different radial distances. Only subtle modulations of the 4 He spectral slopes are observed between Solar Orbiter and ACE. Additionally, the radial gradients of 226−320 keV/nuc 4 He ion intensities between Solar Orbiter and ACE are similar to that of 1.53 MeV H reported by Van Hollebeke et al. (1978, J. Geophys. Res., 83, A10). These observations provide a new addition to the study of the radial dependence of CIR-associated suprathermal ions in the inner heliosphere.