The anomalous state of Uranus's magnetosphere during the Voyager 2 flyby

被引：4

作者：

Jasinski, Jamie M. ^{[1
]}

Cochrane, Corey J. ^{[1
]}

Jia, Xianzhe ^{[2
]}

Dunn, William R. ^{[3
]}

Roussos, Elias ^{[4
]}

Nordheim, Tom A. ^{[1
,5
]}

Regoli, Leonardo H. ^{[5
]}

Achilleos, Nick ^{[3
]}

Krupp, Norbert ^{[4
]}

Murphy, Neil ^{[1
]}

机构：

[1] CALTECH, NASA, Jet Prop Lab, Pasadena, CA 91125 USA

[2] Univ Michigan, Dept Climate & Space Sci & Engn, Ann Arbor, MI USA

[3] UCL, Dept Phys & Astron, London, England

[4] Max Planck Inst Solar Syst Res, Gottingen, Germany

[5] Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA

来源：

NATURE ASTRONOMY | 2025年 / 9卷 / 01期

基金：

美国国家航空航天局;

关键词：

AURORAL KILOMETRIC RADIATION; MAGNETIC-FIELD; PLASMA OBSERVATIONS; SOLAR; MAGNETOPAUSE; RECONNECTION;

D O I：

10.1038/s41550-024-02389-3

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

The Voyager 2 flyby of Uranus in 1986 revealed an unusually oblique and off-centred magnetic field. This single in situ measurement has been the basis of our interpretation of Uranus's magnetosphere as the canonical extreme magnetosphere of the solar system; with inexplicably intense electron radiation belts and a severely plasma-depleted magnetosphere. However, the role of external forcing by the solar wind has rarely been considered in explaining these observations. Here we revisit the Voyager 2 dataset to show that Voyager 2 observed Uranus's magnetosphere in an anomalous, compressed state that we estimate to be present less than 5% of the time. If the spacecraft had arrived only a few days earlier, the upstream solar wind dynamic pressure would have been similar to 20 times lower, resulting in a dramatically different magnetospheric configuration. We postulate that such a compression of the magnetosphere could increase energetic electron fluxes within the radiation belts and empty the magnetosphere of its plasma temporarily. Therefore, the interpretation of Uranus's magnetosphere as being extreme may simply be a product of a flyby that occurred under extreme upstream solar wind conditions.

引用

页码：66 / 74

页数：10