A1 Refereed original research article in a scientific journal
Highly Polarized Type III Storm Observed with Parker Solar Probe
Authors: Pulupa, Marc; Bale, Stuart D.; Jebaraj, Immanuel Christopher; Romeo, Orlando; Krucker, Sam
Publisher: American Astronomical Society
Publishing place: BRISTOL
Publication year: 2025
Journal: Astrophysical Journal Letters
Journal name in source: The Astrophysical Journal Letters
Journal acronym: ASTROPHYS J LETT
Article number: L34
Volume: 987
Issue: 2
Number of pages: 7
ISSN: 2041-8205
eISSN: 2041-8213
DOI: https://doi.org/10.3847/2041-8213/ade5a8
Web address : https://doi.org/10.3847/2041-8213/ade5a8
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/499432650
The Parker Solar Probe (PSP) spacecraft observed a large coronal mass ejection (CME) on 2022 September 5, shortly before closest approach during the 13th PSP solar encounter. For several days following the CME, PSP detected a storm of Type III radio bursts. Stokes parameter analysis of the radio emission indicates that the Type III storm was highly circularly polarized (with fractional polarization up to similar to 0.4). Left-hand circularly polarized (LHC) emission dominated at the start of the storm, transitioning to right-hand circularly polarized (RHC) emission at the crossing of the heliospheric current sheet on September 6. We analyze the properties of this Type III storm. The drift rate of the Type IIIs indicates a constant beam speed of similar to 0.1c, typical for Type III-producing electron beams. The sense of polarization is consistent with fundamental emission generated primarily in the O-mode. The stable and well organized post-CME magnetic field neatly separates the LHC- and RHC-dominated intervals of the storm, with minimal overlap between the senses of polarization. The proximity of PSP to the source region, both in radial distance and in heliographic longitude, makes this event an ideal case study to connect in situ plasma measurements with remote observations of radio emission.
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Funding information in the publication:
Parker Solar Probe was designed, built, and is now operated by the Johns Hopkins Applied Physics Laboratory as part of NASA's Living with a Star (LWS) program under NASA contract NNN06AA01C. Data access and processing were done using SPEDAS (V. Angelopoulos et al. 2019). FIELDS data products are publicly available at the FIELDS SOC webpage: https://fields.ssl.berkeley.edu This research was supported by the International Space Science Institute (ISSI) in Bern, through ISSI International Team project No. 557, "Beam-Plasma Interaction in the Solar Wind and the Generation of Type III Radio Bursts." I.C.J. was supported through the Visiting Scientist program of the International Space Science Institute (ISSI) in Bern. The authors thank the anonymous referee for a detailed and constructive review.
