Journal article
Birkeland currents in Jupiter's magnetosphere observed by the polar-orbiting Juno spacecraft
NATURE ASTRONOMY, Vol.3(10), pp.904-909
10/01/2019
DOI: 10.1038/s41550-019-0819-7
Abstract
The exchange of energy and momentum between the Earth's upper atmosphere and ionosphere, and its space environment (magnetosphere) is regulated by electric currents (called Birkeland currents) flowing along magnetic field lines that connect these two regions of space(1). The associated electric currents flow towards and away from each pole primarily in two concentric conical sheets(2) . It has been expected that powerful sheets of magnetic-field-aligned electric currents would be found in association with the bright Jovian auroras(3). The Juno spacecraft is well positioned to explore Jupiter's polar magnetosphere and sample Birkeland or field-aligned currents and particle distributions. Since July 2016, Juno has maintained a near-polar orbit, passing over both polar regions every 53 days. From this vantage point, Juno's complement of science instruments gathers in situ observations of magnetospheric particles and fields while its remote-sensing infrared and ultraviolet spectrographs and imagers map auroral emissions(4). Here we present an extensive analysis of magnetic field perturbations measured during Juno's transits of Jupiter's polar regions, and thereby demonstrate Birkeland currents associated with Jupiter's auroral emissions. We characterize the magnitude and spatial extent of the currents and we find that they are weaker than anticipated and filamentary in nature. A significant asymmetry is observed between the field perturbations and the current associated with the northern and the southern auroras.
Details
- Title: Subtitle
- Birkeland currents in Jupiter's magnetosphere observed by the polar-orbiting Juno spacecraft
- Creators
- Stavros Kotsiaros - Goddard Space Flight CenterJohn E. P. Connerney - Goddard Space Flight CenterGeorge Clark - Johns Hopkins University Applied Physics LaboratoryFrederic Allegrini - The University of Texas at San AntonioG. Randall Gladstone - Southwest Research InstituteWilliam S. Kurth - University of IowaBarry H. Mauk - Johns Hopkins University Applied Physics LaboratoryJoachim Saur - University of CologneEmma J. Bunce - University of LeicesterDaniel J. Gershmanl - NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USAYasmina M. Martos - Goddard Space Flight CenterThomas K. Greathouse - Southwest Research InstituteScott J. Bolton - Southwest Research InstituteSteven M. Levin - Jet Propulsion Laboratory
- Resource Type
- Journal article
- Publication Details
- NATURE ASTRONOMY, Vol.3(10), pp.904-909
- Publisher
- Springer Nature
- DOI
- 10.1038/s41550-019-0819-7
- ISSN
- 2397-3366
- eISSN
- 2397-3366
- Number of pages
- 6
- Grant note
- ST/P002382/1 / Science and Technology Facilities Council; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC) ST/S000429/1; ST/N000749/1; ST/P002382/1 / STFC; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC) ST/N000749/1 / STFC; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC) Juno project Royal Society Wolfson Research Merit Award; Royal Society
- Language
- English
- Date published
- 10/01/2019
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455274202771
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