Rights statement: Copyright 2013 American Geophysical Union.
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Photoelectrons in the Enceladus plume
AU - Coates, A. J.
AU - Wellbrock, A.
AU - Jones, Geraint H.
AU - Waite, J. H.
AU - Schippers, P.
AU - Thomsen, M. F.
AU - Arridge, C. S.
AU - Tokar, R. L.
N1 - Copyright 2013 American Geophysical Union.
PY - 2013/8
Y1 - 2013/8
N2 - The plume of Enceladus is a remarkable plasma environment containing several charged particle species. These include cold magnetospheric electrons, negative and positive water clusters, charged nanograins, and magnetospheric photoelectrons produced from ionization of neutrals throughout the magnetosphere near Enceladus. Here we discuss observations of a population newly identified by the Cassini Plasma Spectrometer (CAPS) electron spectrometer instrumentphotoelectrons produced in the plume ionosphere itself. These were found during the E19 encounter, in the energetic particle shadow where penetrating particles are absent. Throughout E19, CAPS was oriented away from the ram direction where the clusters and nanograins are observed during other encounters. Plume photoelectrons are also clearly observed during the E9 encounter and are also seen at all other Enceladus encounters where electron spectra are available. This new population, warmer than the ambient plasma population, is distinct from, but adds to, the magnetospheric photoelectrons. Here we discuss the observations and examine the implications, including the ionization source these electrons provide.
AB - The plume of Enceladus is a remarkable plasma environment containing several charged particle species. These include cold magnetospheric electrons, negative and positive water clusters, charged nanograins, and magnetospheric photoelectrons produced from ionization of neutrals throughout the magnetosphere near Enceladus. Here we discuss observations of a population newly identified by the Cassini Plasma Spectrometer (CAPS) electron spectrometer instrumentphotoelectrons produced in the plume ionosphere itself. These were found during the E19 encounter, in the energetic particle shadow where penetrating particles are absent. Throughout E19, CAPS was oriented away from the ram direction where the clusters and nanograins are observed during other encounters. Plume photoelectrons are also clearly observed during the E9 encounter and are also seen at all other Enceladus encounters where electron spectra are available. This new population, warmer than the ambient plasma population, is distinct from, but adds to, the magnetospheric photoelectrons. Here we discuss the observations and examine the implications, including the ionization source these electrons provide.
KW - Enceladus
KW - photoelectrons
KW - plume
KW - ionosphere
KW - Saturn
KW - magnetosphere
KW - IONOSPHERIC PHOTOELECTRONS
KW - ELECTRON SPECTROMETER
KW - MAGNETOSPHERE
KW - PLASMA
KW - SATURN
KW - ATMOSPHERE
KW - VENUS
U2 - 10.1002/jgra.50495
DO - 10.1002/jgra.50495
M3 - Journal article
VL - 118
SP - 5099
EP - 5108
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
SN - 2169-9380
IS - 8
ER -