Solar energetic particles injected inside and outside a magnetic cloud: The widespread solar energetic particle event on 2022 January 20

Abstract

Context. On 2022 January 20, the Energetic Particle Detector (EPD) on board Solar Orbiter measured a solar energetic particle (SEP) event showing unusual first arriving particles from the anti-Sun direction. Near-Earth spacecraft separated 17° in longitude to the west from Solar Orbiter measured classic antisunward-directed fluxes. STEREO-A and MAVEN, separated 18° to the east and 143° to the west from Solar Orbiter respectively, also observed the event, suggesting that particles spread over at least 160° in the heliosphere. Results. Solar Orbiter was embedded in a MC erupting on 16 January from the same active region as that related to the SEP event on 20 January. The SEP event is related to a M5.5 flare and a fast CME-driven shock of 1433 km/s, which injected particles within and outside the MC. Taken together, the hard SEP spectra, the presence of a Type II radio burst, and the co-temporal Type III radio burst being observed from 80 MHz that appears to emanate from the Type II burst, suggest that the shock is likely the main accelerator of the particles. Conclusions. Our detailed analysis of the SEP event strongly suggests that the energetic particles are mainly accelerated by a CME-driven shock and are injected into and outside of a previous MC present in the heliosphere at the time of the particle onset. The sunward-propagating SEPs measured by Solar Orbiter are produced by the injection of particles along the longer (western) leg of the MC still connected to the Sun at the time of the release of the particles. The determined electron propagation path length inside the MC is around 30% longer than the estimated length of the loop leg of the MC itself (based on the graduated cylindrical shell model), which is consistent with the low number of field line rotations.

Accepted by A&A, 23 pages, 19 figures

References in corpus (39)

• The Fermi Gamma-Ray Burst Monitor
• The Solar Orbiter mission -- Science overview
• Ensemble modeling of CMEs using the WSA-ENLIL+Cone model
• The spectral evolution of impulsive solar X-ray flares
• The Driver of Coronal Mass Ejections in the Low Corona: A Flux Rope
• Solar-MACH: An open-source tool to analyze solar magnetic connection configurations
• The Solar Orbiter Science Activity Plan: translating solar and heliospheric physics questions into action
• Quantifying errors in 3D CME parameters derived from synthetic data using white-light reconstruction techniques
• Modeling the evolution and propagation of the 2017 September 9th and 10th CMEs and SEPs arriving at Mars constrained by remote-sensing and in-situ measurement
• Magnetic Field Configuration Models and Reconstruction Methods for Interplanetary Coronal Mass Ejections
• Energetic particle cross-field propagation early in a solar event
• Thermal-nonthermal energy partition in solar flares derived from X-ray, EUV, and bolometric observations
• Spectral properties of large gradual solar energetic particle events - II -Systematic Q/M-dependence of heavy ion spectral breaks
• The 17 April 2021 widespread solar energetic particle event
• Interplanetary magnetic structures guiding solar relativistic particles
• Catalogue of >55 MeV Wide-longitude Solar Proton Events Observed by SOHO, ACE, and the STEREOs at $\approx$1 AU during 2009-2016
• CMEs and SEPs During November-December 2020: A Challenge for Real-Time Space Weather Forecasting
• CME Magnetic Structure and IMF Preconditioning Affecting SEP Transport
• Collection, Collation, and Comparison of 3D Coronal CME Reconstructions
• Statistical results for solar energetic electron spectra observed over 12 years with STEREO/SEPT
• Unusual plasma and particle signatures at Mars and STEREO-A related to CME-CME interaction
• Evidence of a complex structure within the 2013 August 19 coronal mass ejection. Radial and longitudinal evolution in the inner heliosphere
• The unusual widespread solar energetic particle event on 2013 August 19. Solar origin and particle longitudinal distribution
• Using radio triangulation to understand the origin of two subsequent type II radio bursts
• Assessing the Influence of Input Magnetic Maps on Global Modeling of the Solar Wind and CME-driven Shock in the 2013 April 11 Event
• Multiple injections of energetic electrons associated with the flare/CME event on 9 October 2021
• 3D propagation of relativistic solar protons through interplanetary space
• First detection of transverse vertical oscillation during the expansion of coronal loops
• High Spectral Resolution Observation of Decimetric Radio Spikes Emitted by Solar Flares - First Results of the Phoenix-3 Spectrometer
• OCTAD-S: Digital Fast Fourier Transform Spectrometers by FPGA
• Connecting solar flare hard X-ray spectra to in situ electron spectra. A comparison of RHESSI and STEREO/SEPT observations
• Tracking a beam of electrons from the low solar corona into interplanetary space with the Low Frequency Array, Parker Solar Probe and 1 au spacecraft
• Injection of solar energetic particles into both loop legs of a magnetic cloud
• Shock-accelerated electrons during the fast expansion of a coronal mass ejection
• Solar Energetic Particle Time Series Analysis with Python
• On the utility of flux rope models for CME magnetic structure below 30$R_{\odot }$
• Solar Orbiter/RPW antenna calibration in the radio domain and its application to type III burst observations
• The solar cycle 25 multi-spacecraft solar energetic particle event catalog of the SERPENTINE project
• Modeling CME encounters at Parker Solar Probe with OSPREI: Dependence on photospheric and coronal conditions

Cited by in corpus (4)

• On the reason for the widespread energetic storm particle event of 13 March 2023
• CoSEE-Cat: A Comprehensive Solar Energetic Electron event Catalogue obtained from combined in situ and remote-sensing observations from Solar Orbiter -- Catalogue description and first statistical results
• Comparing observations of the closely located JUICE and STEREO-A spacecraft during the widespread solar energetic particle event of 2024 May 13
• Multi-spacecraft observations of the decay phase of solar energetic particle events