Journal article
Energetic Particles and Acceleration Regions Over Jupiter's Polar Cap and Main Aurora: A Broad Overview
Journal of geophysical research. Space physics, Vol.125(3), p.2019
03/01/2020
DOI: 10.1029/2019JA027699
Abstract
Previous Juno mission event studies revealed powerful electron and ion acceleration, to 100s of kiloelectron volts and higher, at low altitudes over Jupiter's main aurora and polar cap (PC; poleward of the main aurora). Here we examine 30–1200 keV JEDI-instrument particle data from the first 16 Juno orbits to determine how common, persistent, repeatable, and ordered these processes are. For the PC regions, we find (1) upward electron angle beams, sometimes extending to megaelectron volt energies, are persistently present in essentially all portions of the polar cap but are generated by two distinct and spatially separable processes. (2) Particle evidence for megavolt downward electrostatic potentials are observable for 80% of the polar cap crossings and over substantial fractions of the PC area. For the main aurora, with the orbit favoring the duskside, we find that (1) three distinct zones are observed that are generally arranged from lower to higher latitudes but sometimes mixed. They are designated here as the diffuse aurora (DifA), Zone-I (ZI(D)) showing primarily downward electron acceleration, and Zone-II (ZII(B)) showing bidirectional acceleration with the upward intensities often greater than downward intensities. (2) ZI(D) and ZII(B) sometimes (but not always) contain, respectively, downward electron inverted Vs and downward proton inverted Vs, (potentials up to 400 kV) but, otherwise, have broadband distributions. (3) Surprisingly, both ZI(D) and ZII(B) can generate equally powerful auroral emissions. It is suggested but demonstrated for intense portions of only one auroral crossing, that ZI(D) and ZII(B) are associated, respectively, with upward and downward electric currents.
Details
- Title: Subtitle
- Energetic Particles and Acceleration Regions Over Jupiter's Polar Cap and Main Aurora: A Broad Overview
- Creators
- B. H. Mauk - Johns Hopkins University Applied Physics LaboratoryG. Clark - Johns Hopkins University Applied Physics LaboratoryG. R. Gladstone - Southwest Research InstituteS. Kotsiaros - University of Maryland, College ParkA. Adriani - Institute for Space Astrophysics and PlanetologyF. Allegrini - The University of Texas at San AntonioF. Bagenal - Laboratory for Atmospheric and Space PhysicsS. J. Bolton - Southwest Research InstituteB. Bonfond - University of LiègeJ. E. P. Connerney - Goddard Space Flight CenterR. W. Ebert - Southwest Research InstituteD. K. Haggerty - Johns Hopkins University Applied Physics LaboratoryP. Kollmann - Johns Hopkins University Applied Physics LaboratoryW. S. Kurth - University of IowaS. M. Levin - Jet Propulsion LaboratoryC. P. Paranicas - Johns Hopkins University Applied Physics LaboratoryA. M. Rymer - Johns Hopkins University Applied Physics Laboratory
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.125(3), p.2019
- DOI
- 10.1029/2019JA027699
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Grant note
- DOI: 10.13039/100006197, name: Marshall Space Flight Center, award: New Frontiers Program
- Language
- English
- Date published
- 03/01/2020
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455280402771
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