Reference : Discrete and broadband electron acceleration in Jupiter's powerful aurora
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/215448
Discrete and broadband electron acceleration in Jupiter's powerful aurora
English
Mauk, B. H. mailto [The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA;]
Haggerty, D. K. [The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA]
Paranicas, C. [The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA]
Clark, G. [The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA]
Kollmann, P. [The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA]
Rymer, A. M. [The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA]
Bolton, S. J. [Southwest Research Institute, San Antonio, Texas, USA]
Levin, S. M. [Jet Propulsion Laboratory, Pasadena, California, USA]
Adriani, A. [Instituto Nazionale di Astrofisica-Instituo di Astofisica e Planetologia Spaziali, Roma, Italy]
Allegrini, F. [Southwest Research Institute, San Antonio, Texas, USA; Physics and Astronomy Department, University of Texas at San Antonio, San Antonio, Texas, USA]
Bagenal, F. [University of Colorado, Boulder, Colorado, USA]
Bonfond, Bertrand mailto [Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP) >]
Connerney, J. E. P. [NASA Goddard Space Flight Center, Greenbelt, Maryland, USA]
Gladstone, G. R. [Southwest Research Institute, San Antonio, Texas, USA]
Kurth, W. S. [University of Iowa, Iowa City, Iowa, USA]
McComas, D. J. [Southwest Research Institute, San Antonio, Texas, USA; Princeton University, Princeton, New Jersey, USA]
Valek, P. [Southwest Research Institute, San Antonio, Texas, USA)]
1-Sep-2017
Nature
549
66-69
Yes
International
[en] Jupiter ; aurora ; Juno
[en] The most intense auroral emissions from Earth's polar regions, called discrete for their sharply defined spatial configurations, are generated by a process involving coherent acceleration of electrons by slowly evolving, powerful electric fields directed along the magnetic field lines that connect Earth's space environment to its polar regions. In contrast, Earth's less intense auroras are generally caused by wave scattering of magnetically trapped populations of hot electrons (in the case of diffuse aurora) or by the turbulent or stochastic downward acceleration of electrons along magnetic field lines by waves during transitory periods (in the case of broadband or Alfvénic aurora). Jupiter's relatively steady main aurora has a power density that is so much larger than Earth's that it has been taken for granted that it must be generated primarily by the discrete auroral process. However, preliminary in situ measurements of Jupiter's auroral regions yielded no evidence of such a process. Here we report observations of distinct, high-energy, downward, discrete electron acceleration in Jupiter's auroral polar regions. We also infer upward magnetic-field-aligned electric potentials of up to 400 kiloelectronvolts, an order of magnitude larger than the largest potentials observed at Earth. Despite the magnitude of these upward electric potentials and the expectations from observations at Earth, the downward energy flux from discrete acceleration is less at Jupiter than that caused by broadband or stochastic processes, with broadband and stochastic characteristics that are substantially different from those at Earth.
Space sciences, Technologies and Astrophysics Research - STAR
Researchers ; Professionals ; General public
http://hdl.handle.net/2268/215448
10.1038/nature23648
http://adsabs.harvard.edu/abs/2017Natur.549...66M

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