Simultaneous Mars-orbit observations reveal Kelvin-Helmholtz instability–driven bulk atmospheric ion escape

Chi Zhang; Chuanfei Dong; Gangkai Poh; Jasper Halekas; Xuanye Ma; Ruhunusiri Suranga; Kathleen G. Hanley; Han-Wen Shen; Hongyang Zhou; Xinmin Li; Liang Wang; Jiawei Gao; Shannon Curry; Christian Mazelle

doi:10.1126/sciadv.aed9072

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Simultaneous Mars-orbit observations reveal Kelvin-Helmholtz instability–driven bulk atmospheric ion escape

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Simultaneous Mars-orbit observations reveal Kelvin-Helmholtz instability–driven bulk atmospheric ion escape

Chi Zhang, Chuanfei Dong, Gangkai Poh, Jasper Halekas, Xuanye Ma, Ruhunusiri Suranga, Kathleen G. Hanley, Han-Wen Shen, Hongyang Zhou, Xinmin Li, …

Science advances, Vol.12(31), eaed9072

07/31/2026

DOI: 10.1126/sciadv.aed9072

PMID: 42536743

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Abstract

Atmospheric ion escape driven by the solar wind is a key process controlling the long-term loss of the Martian atmosphere. Localized plasma clouds can carry substantial fluxes of planetary ions away from Mars, representing episodes of bulk escape. However, their origin has remained unclear due to the absence of simultaneous upstream measurements. Using joint observations from the MAVEN and Tianwen-1 missions, which provide real-time upstream monitoring, we present direct evidence that these plasma clouds are nonlinear wave packets generated by the Kelvin-Helmholtz instability (KHI). The spatial scale of KH waves is constrained for the first time via two-point measurements. Ion fluxes within plasma clouds are one to two orders of magnitude higher than those in typical steady-state escape channels. Our results indicate that KHI is an important process for solar wind coupling to planetary upper atmospheres and plays a crucial role in shaping atmospheric ion escape for unmagnetized planets. MAVEN and Tianwen-1 link Martian plasma clouds to Kelvin-Helmholtz instability, with ion loss 10× to 100× higher than steady state.

Space Sciences

Earth, Environmental, Ecological, and Space Sciences

Planetary Science

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Details

Title: Subtitle: Simultaneous Mars-orbit observations reveal Kelvin-Helmholtz instability–driven bulk atmospheric ion escape
Creators: Chi Zhang - Boston University
Chuanfei Dong - Boston University
Gangkai Poh - Goddard Space Flight Center
Jasper Halekas - University of Iowa
Xuanye Ma - Embry–Riddle Aeronautical University
Ruhunusiri Suranga - University of Colorado Boulder
Kathleen G. Hanley - University of California, Berkeley
Han-Wen Shen - University of Iowa
Hongyang Zhou - Boston University
Xinmin Li - Boston University
Liang Wang - Boston University
Jiawei Gao - Boston University
Shannon Curry - University of Colorado Boulder
Christian Mazelle - Centre National de la Recherche Scientifique
Resource Type: Journal article
Publication Details: Science advances, Vol.12(31), eaed9072
DOI: 10.1126/sciadv.aed9072
PMID: 42536743
NLM abbreviation: Sci Adv
ISSN: 2375-2548
eISSN: 2375-2548
Publisher: American Association for the Advancement of Science
Alternative title: Kelvin-Helmholtz instability–driven bulk ion escape at Mars
Language: English
Date published: 07/31/2026
Academic Unit: Physics and Astronomy
Record Identifier: 9985215014002771

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