A radio oval above Earth’s auroral oval

Siyuan Wu; Daniel K. Whiter; Laurent Lamy; Ulrich Taubenschuss; Philippe Zarka; Brieuc Collet; Xiangyu Wang; Georg Fischer; Hao Ning; Yao Chen; Mengmeng Wang; Shengyi Ye; Zhonghua Yao; William S. Kurth; Xiaoli Luan

doi:10.1126/sciadv.aec4114

Back

Journal article

Open access

Peer reviewed

A radio oval above Earth’s auroral oval

Siyuan Wu, Daniel K. Whiter, Laurent Lamy, Ulrich Taubenschuss, Philippe Zarka, Brieuc Collet, Xiangyu Wang, Georg Fischer, Hao Ning, Yao Chen, …

Science advances, Vol.12(13), eaec4114

03/27/2026

DOI: 10.1126/sciadv.aec4114

PMID: 41894503

Files and links (1)

url

https://doi.org/10.1126/sciadv.aec4114View

Published (Version of record) Open Access

Abstract

Auroral kilometric radiation (AKR), Earth’s strongest radio emission, has long been associated with discrete auroras and electrons near a few kilo–electron volt (keV) range. However, auroras also occur in diffuse forms with broader electron energies, raising the question of why AKR has not been observed above diffuse auroras or linked to electrons outside the kilo–electron volt population. Comprehensive AKR source distributions have remained elusive because of observational limitations, and their local-time coverage remains largely unknown. Using spacecraft measurements, we identify a “radio oval” above the optical auroral oval, spanning the full local-time range, where AKR is emitted over both discrete and diffuse auroras. The AKR source electrons display diverse precipitation features, including monoenergetic (peak flux at 3.82 kilo–electron volts), broadband (1.34 kilo–electron volts), low-energy (0.47 kilo–electron volts), and diffuse types (>1 kilo–electron volt). These results reveal that the cyclotron maser instability—the mechanism driving AKR—can arise in diverse plasma environments, broadening our understanding of both AKR generation and auroral complexity. Radio waves called AKR radiate above auroras, driven by diverse electron acceleration and precipitation processes.

Astronomy

Geophysics

Earth, Environmental, Ecological, and Space Sciences

SciAdv r-articles

Details

Title: Subtitle: A radio oval above Earth’s auroral oval
Creators: Siyuan Wu - University of Southampton
Daniel K. Whiter - University of Southampton
Laurent Lamy - Centre National de la Recherche Scientifique
Ulrich Taubenschuss - Czech Academy of Sciences, Institute of Atmospheric Physics
Philippe Zarka - Centre National de la Recherche Scientifique
Brieuc Collet - Centre National de la Recherche Scientifique
Xiangyu Wang - Shandong University
Georg Fischer - University of Graz
Hao Ning - Institut des Sciences Moléculaires
Yao Chen - Institut des Sciences Moléculaires
Mengmeng Wang - Swedish Institute of Space Physics
Shengyi Ye - Southern University of Science and Technology
Zhonghua Yao - Planetary Science Institute
William S. Kurth - University of Iowa
Xiaoli Luan - University of Science and Technology of China
Resource Type: Journal article
Publication Details: Science advances, Vol.12(13), eaec4114
DOI: 10.1126/sciadv.aec4114
PMID: 41894503
NLM abbreviation: Sci Adv
ISSN: 2375-2548
eISSN: 2375-2548
Publisher: American Association for the Advancement of Science
Grant note: Science and Technology Facilities Council (STFC) of the UK: ST/Y002121/1 Austrian Science Fund FWF: 10.55776/I6710
This work was supported by the Science and Technology Facilities Council (STFC) of the UK under grant ST/Y002121/1. G.F. acknowledges support from the Austrian Science Fund FWF via project 10.55776/I6710.
Alternative title: A radio oval above Earth’s auroral oval
Language: English
Date published: 03/27/2026
Academic Unit: Physics and Astronomy
Record Identifier: 9985149578302771

Metrics

1 Record Views

See more details