Imperial College London
Alternate

ProfessorMicheleDougherty

Faculty of Natural Sciences, Department of Physics

Head of Department of Physics, Professor of Space Physics
 
 
 
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Contact

 

+44 (0)20 7594 7770m.dougherty Website

 
 
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Assistant

 

Ms Lida Mnatsakanian +44 (0)20 7594 7503

 
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Location

 

Blackett 900aBlackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Sorba:2017:10.1002/2016JA023544,
author = {Sorba, AM and Achilleos, NA and Guio, P and Arridge, CS and Pilkington, NM and Masters, A and Sergis, N and Coates, AJ and Dougherty, MK},
doi = {10.1002/2016JA023544},
journal = {Journal of Geophysical Research: Space Physics},
pages = {1572--1589},
title = {Modeling the compressibility of Saturn's magnetosphere in response to internal and external influences},
url = {http://dx.doi.org/10.1002/2016JA023544},
volume = {122},
year = {2017}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The location of a planetary magnetopause is principally determined by the balance between solar wind dynamic pressure DP and magnetic and plasma pressures inside the magnetopause boundary. Previous empirical studies assumed that Saturn's magnetopause standoff distance varies as  math formula and measured a constant compressibility parameter α corresponding to behavior intermediate between a vacuum dipole appropriate for Earth (α≈6) and a more easily compressible case appropriate for Jupiter (α≈4). In this study we employ a 2-D force balance model of Saturn's magnetosphere to investigate magnetospheric compressibility in response to changes in DP and global hot plasma content. For hot plasma levels compatible with Saturn observations, we model the magnetosphere at a range of standoff distances and estimate the corresponding DP values by assuming pressure balance across the magnetopause boundary. We find that for “average” hot plasma levels, our estimates of α are not constant with DP but vary from ∼4.8 for high DP conditions, when the magnetosphere is compressed (≤25 RS), to ∼3.5 for low DP conditions. This corresponds to the magnetosphere becoming more easily compressible as it expands. We find that the global hot plasma content influences magnetospheric compressibility even at fixed DP, with α estimates ranging from ∼5.4 to ∼3.3 across the range of our parameterized hot plasma content. We suggest that this behavior is predominantly driven by reconfiguration of the magnetospheric magnetic field into a more disk-like structure under such conditions. In a broader context, the compressibility of the magnetopause reveals information about global stress balance in the magnetosphere.
AU  - Sorba,AM
AU  - Achilleos,NA
AU  - Guio,P
AU  - Arridge,CS
AU  - Pilkington,NM
AU  - Masters,A
AU  - Sergis,N
AU  - Coates,AJ
AU  - Dougherty,MK
DO  - 10.1002/2016JA023544
EP  - 1589
PY  - 2017///
SN  - 2169-9402
SP  - 1572
TI  - Modeling the compressibility of Saturn's magnetosphere in response to internal and external influences
T2  - Journal of Geophysical Research: Space Physics
UR  - http://dx.doi.org/10.1002/2016JA023544
UR  - http://hdl.handle.net/10044/1/44926
VL  - 122
ER  -
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