Imperial College London
Alternate

ProfessorMarinaGaland

Faculty of Natural Sciences, Department of Physics

Professor in Planetary Science
 
 
 
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Contact

 

m.galand Website

 
 
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Location

 

Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Cao:2020:10.1029/2019je006252,
author = {Cao, Y and Wellbrock, A and Coates, AJ and CaroCarretero, R and Jones, GH and Cui, J and Galand, M and Dougherty, MK},
doi = {10.1029/2019je006252},
journal = {Journal of Geophysical Research: Planets},
pages = {1--13},
title = {Fieldaligned photoelectron energy peaks at high altitude and on the nightside of titan},
url = {http://dx.doi.org/10.1029/2019je006252},
volume = {125},
year = {2020}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The ionization of N urn:x-wiley:jgre:media:jgre21272:jgre21272-math-0001 by strong solar He II 30.4nm photons produces distinctive spectral peaks near 24.1 eV in Titan's upper atmosphere, which have been observed by the Electron Spectrometer (ELS) as part of the Cassini Plasma Spectrometer. The ELS observations reveal that, in addition to the dayside, photoelectron peaks were also detected on the deep nightside where photoionization is switched off, as well as at sufficiently high altitudes where the ambient neutral density is low. These photoelectron peaks are unlikely to be produced locally but instead must be contributed by transport along the magnetic field lines from their dayside source regions. In this study, we present a statistical survey of all photoelectron peaks identified with an automatic finite impulse response algorithm based on the available ELS data accumulated during 56 Titan flybys. The spatial distribution of photoelectron peaks indicates that most photoelectrons detected at an altitude above 4,000 km and a solar zenith angle above 100° are field aligned, which is consistent with the scenario of photoelectron transport along the magnetic field lines. Our analysis also reveals the presence of a photoelectron gap in the deep nightside ionosphere where almost no photoelectrons were detected. It appears to be very difficult for photoelectrons to travel to this region, and such a feature may not be driven by the changes in the orientation between the solar and corotation wakes.
AU  - Cao,Y
AU  - Wellbrock,A
AU  - Coates,AJ
AU  - CaroCarretero,R
AU  - Jones,GH
AU  - Cui,J
AU  - Galand,M
AU  - Dougherty,MK
DO  - 10.1029/2019je006252
EP  - 13
PY  - 2020///
SN  - 2169-9097
SP  - 1
TI  - Fieldaligned photoelectron energy peaks at high altitude and on the nightside of titan
T2  - Journal of Geophysical Research: Planets
UR  - http://dx.doi.org/10.1029/2019je006252
UR  - https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JE006252
UR  - http://hdl.handle.net/10044/1/77038
VL  - 125
ER  -
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