Unusually long path length for a nearly scatter-free solar particle event observed by Solar Orbiter at 0.43 au

• DOI: 10.5194/egusphere-egu24-2823
• Publication Date: 2024-03-08T12:31:46Z
• Authors: Robert F. Wimmer-...; Liu Yang; Alexander Kollhoff; Raúl Gomez-Herrero; Javier Rodriguez-...; Francisco Espinosa; Ignacio Cernuda; George C. Ho; Glenn M. Mason; Alexander Warmuth; Christopher J, Owen; Luciano Rodriguez; Daria Shukhobodskaia; Lars Berger; Patrick Kühl; Bernd Heber; Linghua Wang; Radoslav Bucik; Olga Malandraki
• Keywords: Orbiter; Particle (ecology)

Solar energetic particles (SEPs) are bound to the interplanetary magnetic field (IMF) by Lorentz force. The expansion of IMF close Sun focuses particle pitch-angle distribution, and scattering counteracts this focusing. Orbiter observed an unusual solar event on 9 April 2022 when it was at 0.43 astronomical units (au) from Sun. inferred along which SEPs traveled about three times longer than nominal length Parker spiral.Nevertheless, distribution is highly anisotropic, electrons ions appear be streaming same structures. angular width population estimated approximately 30 degrees. anisotropic ion beam for more 12 h. This may due low level fluctuations in IMF, turn very probably being inside coronal mass ejection. slow small rotation suggests a flux-rope structure. Small flux dropouts associated with changes pitch angle, explained different tubes connecting locations flare region. unusually long path have propagated virtually scatter-free together short-term offer excellent opportunities study transport within offers especially rich number unique observations that can used limit SEP models.