Few Made It Out: A Multi-Messenger Study of an In Situ Solar Energetic Electron Event Driven by a Solar Jet

Abstract

When in situ solar energetic electron (SEE) events are closely associated with nonthermal flares, the escaping electron population is frequently observed to be much smaller than the nonthermal-radiation-emitting population near the solar surface. If a single accelerated population drives both signatures, the physical mechanism causing this severe deficit of upward-propagating electrons remains poorly understood.Focusing on one of the 2022 November 10--12 SEE events associated with recurrent solar jets and interplanetary type III radio bursts, we present a new, combined microwave--X-ray analysis using the Expanded Owens Valley Solar Array (EOVSA) and the Spectrometer/Telescope for Imaging X-rays (STIX) aboard Solar Orbiter. This synergy enables, for the first time for such an event, spatially resolved diagnostics over a broad energy spectrum of the near-Sun energetic electrons, complemented by in situ measurements made by spacecraft at multiple heliocentric longitudes and distances. Consistent with earlier results based on in situ and X-ray data, our results show that only 0.1--1\% of energetic electrons escape into interplanetary space. Crucially, the new microwave spectral imaging analysis suggests that energetic electrons are strongly concentrated in a compact region just above a mini-flare arcade at the base of the jet spire, and that their number density decreases by at least two orders of magnitude in the direction of the jet spire away from this region. This steep gradient, revealed by the microwave diagnostics, points to efficient local acceleration and trapping in the region analogous to the above-the-looptop ``magnetic bottle'' region in major eruptive flares, allowing only a small fraction of electrons to access open magnetic field lines and enter interplanetary space.

Figures (13)

• Figure 1: (a) Spacecraft configuration on 2022 November 12. The black arrow represents the longitude of AR 13141. The solar wind speed is assumed to be $400\ \mathrm{km}\ \mathrm{s}^{-2}$. (b) Open-closed field map of CR 2264 derived from the 3D MAS model. The background is SDO/AIA 193 Å map reprojected into the Carrington coordinates. The red and blue contours mark the regions of open magnetic fields of positive and negative polarity, respectively. The black arrow indicates the jet region, which is associated with positive open magnetic field lines at the western edge of AR 13141. (c) Full-disk image from the SDO/AIA 171 Å channel at 17:49:45 UT on 2022 November 11. The black rectangle encloses the AR 13141.
• Figure 2: Electron differential flux observed by SolO/EPD (a), STEREO-A/SEPT (b), and WIND/3DP (c), respectively. The orange-shaded region shows the 2022 November 12 SEE event observed by both EOVSA and SolO/STIX, which is selected for spectral analysis. The seven red arrows with red numbers indicate the SEE events that can be clearly isolated in SolO/EPD's 66 keV channel, and are also marked as red in Figures \ref{['Fig_overview1']}(a) and (e).
• Figure 3: Relationship between the SEE events and GOES, STIX, and type III radio bursts during the period between 2022 November 10 at 11:00 UT and 2022 November 12 at 20:00 UT. The arrows labeled 1 to 25 indicate the times of the 25 SEE events identified by Lario2024, among which seven of them marked as red can be clearly identified in the 66 keV channel observed by SolO shown as red arrows in Figure \ref{['in-situ_obs']}. (a) GOES SXR light curve. The red dashed lines correspond to the SEEs event reported by Lario2024, with the vertical heights representing the energy range of the SEEs. The arrows with (without)orange color mark the SEEs associated with (without) the EUV jets. (b) SolO/STIX light curve at three different energy channels. Red arrows indicate SEEs associated with X-ray flares that have corresponding STIX imaging data, while uncolored arrows mark SEEs without available STIX imaging data. Blue cross markers indicate STIX flares with imaging data that are not associated with SEEs. (c) Interplanetary type III radio bursts recorded by STEREO-A/WAVES. Green arrows indicate SEEs associated with type III radio bursts. All the SEE events but one (marked in a gray arrow), are associated with type III radio bursts. (d) Magnetic longitudinal separation between AR 13141 and SolO, PSP, WIND, and STEREO-A. (e)-(h) correspond to the same quantities as (a)-(d), but are presented over a different time interval.
• Figure 4: STIX sources at the 4--10 keV energy range (50$\%$ contour of the maximum intensity at each energy channel), overlaid with SDO/AIA 171 Å image at 17:50 UT on 2022 November 11. The AIA field of view is the region corresponding to the black box shown in Figure \ref{['Fig_solar_mach_spacecraft']}(b). The red contours correspond to STIX sources associated with SEEs, while the blue contours correspond to STIX sources without SEEs.
• Figure 5: Overview of the time history of the 2022 November 12 jet event: (a) GOES SXR light curve. (b) Total-power radio dynamic spectrum in the microwave range observed by EOVSA, with the black curve representing the light curve at 6 GHz (the data gap region is indicated by a gray background). The gray dashed lines indicate the full-width-at-half-maximum (FWHM) duration of the 6 GHz microwave emission, which lasts 21 s. (c) STIX-observed HXR light curves at different energy channels. The pre-flare background has been subtracted. The gray dashed line indicates the FWHM duration of the 25–50 keV burst, which lasts 19 s.