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{Chadney:2022:10.1016/j.icarus.2021.114724,
author = {Chadney, JM and Koskinen, TT and Hu, X and Galand, M and Lavvas, P and Unruh, Y and Serigano, J and Hörst, SM and Yelle, RV},
doi = {10.1016/j.icarus.2021.114724},
journal = {Icarus},
pages = {1--16},
title = {Energy deposition in Saturn's equatorial upper atmosphere},
url = {http://dx.doi.org/10.1016/j.icarus.2021.114724},
volume = {372},
year = {2022}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - We construct Saturn equatorial neutral temperature and density profiles of H, H2, He, and CH4, between 10−12 and 1 bar using measurements from Cassini’s Ion Neutral Mass Spectrometer (INMS) taken during the spacecraft’s final plunge into Saturn’s atmosphere on 15 September 2017, combined with previous deeper atmospheric measurements from the Cassini Composite InfraRed Spectrometer (CIRS) and from the UltraViolet Imaging Spectrograph (UVIS). These neutral profiles are fed into an energy deposition model employing soft X-ray and Extreme UltraViolet (EUV) solar fluxes at a range of spectral resolutions (λ = 4×10−3 nm to 1 nm) assembled from TIMED/SEE, from SOHO/SUMER, and from the Whole Heliosphere Interval (WHI) quiet Sun campaign. Our energy deposition model calculates ion production rate profiles through photo-ionisation and electron-impact ionisation processes, as well as rates of photo-dissociation of CH4. The ion reaction rate profiles we determine are important to obtain accurate ion density profiles, meanwhile methane photo-dissociation is key to initiate complex organic chemical processes. We assess the importance of spectral resolution in the energy deposition model by using a high-resolution H2 photo-absorption cross section, which has the effect of producing additional ionisation peaks near 800 km altitude. We find that these peaks are still formed when using low resolution (λ = 1 nm) or mid-resolution (λ = 0.1 nm) solar spectra, as long as high-resolution cross sections are included in the model.
AU  - Chadney,JM
AU  - Koskinen,TT
AU  - Hu,X
AU  - Galand,M
AU  - Lavvas,P
AU  - Unruh,Y
AU  - Serigano,J
AU  - Hörst,SM
AU  - Yelle,RV
DO  - 10.1016/j.icarus.2021.114724
EP  - 16
PY  - 2022///
SN  - 0019-1035
SP  - 1
TI  - Energy deposition in Saturn's equatorial upper atmosphere
T2  - Icarus
UR  - http://dx.doi.org/10.1016/j.icarus.2021.114724
UR  - https://www.sciencedirect.com/science/article/pii/S0019103521003791?via%3Dihub
UR  - http://hdl.handle.net/10044/1/92080
VL  - 372
ER  -
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