Loss rates of Europa's tenuous atmosphere
Journal
Date Issued
2016
Author(s)
•
•
•
•
Cassidy, Timothy
•
Jia, Xianzhe
•
Shematovich, Valery
Abstract
Loss processes in Europa's tenuous atmosphere are dominated by plasma-neutral interactions. Based on the updated data of the plasma conditions in the vicinity of Europa (Bagenal et al. 2015), we provide estimations of the atmosphere loss rates for the H2O, O2 and H2 populations. Due to the high variability of the plasma proprieties, we perform our investigation for three sample plasma environment cases identified by Bagenal et al. as hot/low density, cold/high density, and an intermediate case. The role of charge-exchange interactions between atmospheric neutrals and three different plasma populations, i.e. magnetospheric, pickup, and ionospheric ions, is examined in detail. Our assumptions related to the pickup and to the ionospheric populations are based on the model by Sittler et al. (2013). We find that O2-O2+ charge-exchange is the fastest loss process for the most abundant atmospheric species O2, though this loss process has been neglected in previous atmospheric models. Using both the revised O2 column density obtained from the EGEON model (Plainaki et al., 2013) and the current loss rate estimates, we find that the upper limit for the volume integrated loss rate due to O2-O2+ charge exchange is in the range (13-51)×1026 s-1, depending on the moon's orbital phase and illumination conditions. The results of the current study are relevant to the investigation of Europa's interaction with Jupiter's magnetospheric plasma.
Volume
130
Start page
14
Issn Identifier
0032-0633
Ads BibCode
2016P&SS..130...14L
Rights
open.access
File(s)![Thumbnail Image]()
![Thumbnail Image]()
Loading...
Name
loss_rates_Sept_revised.pdf
Description
preprint
Size
1.02 MB
Format
Adobe PDF
Checksum (MD5)
c61c44f531225ebcbf348b6b0ef038b6
Loading...
Name
1-s2.0-S0032063316000052-main.pdf
Description
[Administrators only]
Size
445.99 KB
Format
Adobe PDF
Checksum (MD5)
e261080d256fc9c32f2e6bc431453e7d