MESSENGER Observations of Mercury's Planetary Ion Escape Rates and Their Dependence on True Anomaly Angle-Reference-Cited by-同舟云学术

MESSENGER Observations of Mercury's Planetary Ion Escape Rates and Their Dependence on True Anomaly Angle

Published:2024-07-06 Issue:13 Volume:51 Page:
ISSN:0094-8276
Container-title:Geophysical Research Letters
language:en
Short-container-title:Geophysical Research Letters

Author:

Sun Weijie¹^ORCID,Dewey Ryan M.²^ORCID,Jia Xianzhe²^ORCID,Raines Jim M.²^ORCID,Slavin James A.²^ORCID,Chen Yuxi³^ORCID,Phan Tai¹^ORCID,Poh Gangkai⁴⁵^ORCID,Xu Shaosui¹^ORCID,Milillo Anna⁶^ORCID,Lillis Robert¹^ORCID,Saito Yoshifumi⁷^ORCID,Livi Stefano²⁸,Orsini Stefano⁶

Affiliation:

1. Space Sciences Laboratory University of California Berkeley CA USA

2. Department of Climate and Space Sciences and Engineering University of Michigan Ann Arbor MI USA

3. Center for Space Physics and Department of Astronomy Boston University Boston MA USA

4. NASA Goddard Space Flight Center Greenbelt MD USA

5. Center for Research and Exploration in Space Sciences and Technology II Catholic University of America Washington DC USA

6. Institute of Space Astrophysics and Planetology INAF Rome Italy

7. Japan Aerospace Exploration Agency Institute of Space and Astronautical Science Sagamihara Japan

8. Southwest Research Institute San Antonio TX USA

Abstract

AbstractThis study investigates the escape of Mercury's sodium‐group ions (Na+‐group, including ions with m/q from 21 to 30 amu/e) and their dependence on true anomaly angle (TAA), that is, Mercury's orbital phase around the Sun, using measurements from MESSENGER. The measurements are categorized into solar wind, magnetosheath, and magnetosphere, and further divided into four TAA intervals. Na+‐group ions form escape plumes in the solar wind and magnetosheath, with higher fluxes along the solar wind's motional electric field. The total escape rates vary from 0.2 to 1 × 1025 atoms/s with the magnetosheath being the main escaping region. These rates exhibit a TAA dependence, peaking near the perihelion and similar during Mercury's remaining orbit. Despite Mercury's tenuous exosphere, Na+‐group ions escape rate is comparable to other inner planets. This can be attributed to several processes, including that Na+‐group ions may include several ion species, efficient photoionization frequency for elements within Na‐group, etc.

Funder

Planetary Science Division

National Science Foundation

National Aeronautics and Space Administration

Johns Hopkins University

Publisher

American Geophysical Union (AGU)

Link

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2023GL107689

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