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Cassini observations of ionospheric plasma in Saturn's magnetotail lobes

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Cassini observations of ionospheric plasma in Saturn's magnetotail lobes. / Felici, Mariana; Arridge, Christopher Stephen; Coates, A. J. et al.
In: Journal of Geophysical Research: Space Physics, Vol. 121, No. 1, 01.2016, p. 338-357.

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Harvard

Felici, M, Arridge, CS, Coates, AJ, Badman, SV, Dougherty, MK, Jackman, CM, Kurth, W, Melin, H, Mitchell, DG, Reisenfeld, D & Sergis, N 2016, 'Cassini observations of ionospheric plasma in Saturn's magnetotail lobes', Journal of Geophysical Research: Space Physics, vol. 121, no. 1, pp. 338-357. https://doi.org/10.1002/2015JA021648

APA

Felici, M., Arridge, C. S., Coates, A. J., Badman, S. V., Dougherty, M. K., Jackman, C. M., Kurth, W., Melin, H., Mitchell, D. G., Reisenfeld, D., & Sergis, N. (2016). Cassini observations of ionospheric plasma in Saturn's magnetotail lobes. Journal of Geophysical Research: Space Physics, 121(1), 338-357. https://doi.org/10.1002/2015JA021648

Vancouver

Felici M, Arridge CS, Coates AJ, Badman SV, Dougherty MK, Jackman CM et al. Cassini observations of ionospheric plasma in Saturn's magnetotail lobes. Journal of Geophysical Research: Space Physics. 2016 Jan;121(1):338-357. Epub 2015 Dec 30. doi: 10.1002/2015JA021648

Author

Felici, Mariana ; Arridge, Christopher Stephen ; Coates, A. J. et al. / Cassini observations of ionospheric plasma in Saturn's magnetotail lobes. In: Journal of Geophysical Research: Space Physics. 2016 ; Vol. 121, No. 1. pp. 338-357.

Bibtex

@article{6e0a17e2b9c04fe482728b17acffa50d,
title = "Cassini observations of ionospheric plasma in Saturn's magnetotail lobes",
abstract = "Studies of Saturn's magnetosphere with the Cassini mission have established the importance of Enceladus as the dominant mass source for Saturn's magnetosphere. It is well known that the ionosphere is an important mass source at Earth during periods of intense geomagnetic activity but lesser attention has been dedicated to study the ionospheric mass source at Saturn. In this paper we describe a case study of data from Saturn's magnetotail, when Cassini was located at ∼2200 hours Saturn local time at 36 RS from Saturn. During several entries into the magnetotail lobe, tailward-flowing cold electrons and a cold ion beam were observed directly adjacent to the plasma sheet and extending deeper into the lobe. The electrons and ions appear to be dispersed, dropping to lower energies with time. The composition of both the plasma sheet and lobe ions show very low fluxes (sometimes zero within measurement error) of water group ions. The magnetic field has a swept-forward configuration which is atypical for this region and the total magnetic field strength larger than expected at this distance from the planet. Ultraviolet auroral observations show a dawn brightening and upstream heliospheric models suggest that the magnetosphere is being compressed by a region of high solar wind ram pressure. We interpret this event as the observation of ionospheric outflow in Saturn's magnetotail. We estimate a number flux between 2.95±0.43×109 1.43±0.21×1010 cm-2 s-1, one or about two orders magnitude larger than suggested by steady state MHD models, with a mass source between 1.4×102 and 1.1×103 kg/s. After considering several configurations for the active atmospheric regions, we consider as most probable the main auroral oval, with associated mass source between 49.7±13.4 and 239.8±64.8 kg/s for an average auroral oval, and 10±4 and 49±23 kg/s for the specific auroral oval morphology found during this event. It is not clear how much of this mass is trapped within the magnetosphere and how much is lost to the solar wind.",
author = "Mariana Felici and Arridge, {Christopher Stephen} and Coates, {A. J.} and Badman, {Sarah Victoria} and Dougherty, {M. K.} and Jackman, {Caitriona M.} and William Kurth and Henrik Melin and Mitchell, {Donald G.} and Dan Reisenfeld and Nicholas Sergis",
note = "An edited version of this paper was published by AGU. Copyright 2016 American Geophysical Union",
year = "2016",
month = jan,
doi = "10.1002/2015JA021648",
language = "English",
volume = "121",
pages = "338--357",
journal = "Journal of Geophysical Research: Space Physics",
issn = "2169-9402",
publisher = "Blackwell Publishing Ltd",
number = "1",

}

RIS

TY - JOUR

T1 - Cassini observations of ionospheric plasma in Saturn's magnetotail lobes

AU - Felici, Mariana

AU - Arridge, Christopher Stephen

AU - Coates, A. J.

AU - Badman, Sarah Victoria

AU - Dougherty, M. K.

AU - Jackman, Caitriona M.

AU - Kurth, William

AU - Melin, Henrik

AU - Mitchell, Donald G.

AU - Reisenfeld, Dan

AU - Sergis, Nicholas

N1 - An edited version of this paper was published by AGU. Copyright 2016 American Geophysical Union

PY - 2016/1

Y1 - 2016/1

N2 - Studies of Saturn's magnetosphere with the Cassini mission have established the importance of Enceladus as the dominant mass source for Saturn's magnetosphere. It is well known that the ionosphere is an important mass source at Earth during periods of intense geomagnetic activity but lesser attention has been dedicated to study the ionospheric mass source at Saturn. In this paper we describe a case study of data from Saturn's magnetotail, when Cassini was located at ∼2200 hours Saturn local time at 36 RS from Saturn. During several entries into the magnetotail lobe, tailward-flowing cold electrons and a cold ion beam were observed directly adjacent to the plasma sheet and extending deeper into the lobe. The electrons and ions appear to be dispersed, dropping to lower energies with time. The composition of both the plasma sheet and lobe ions show very low fluxes (sometimes zero within measurement error) of water group ions. The magnetic field has a swept-forward configuration which is atypical for this region and the total magnetic field strength larger than expected at this distance from the planet. Ultraviolet auroral observations show a dawn brightening and upstream heliospheric models suggest that the magnetosphere is being compressed by a region of high solar wind ram pressure. We interpret this event as the observation of ionospheric outflow in Saturn's magnetotail. We estimate a number flux between 2.95±0.43×109 1.43±0.21×1010 cm-2 s-1, one or about two orders magnitude larger than suggested by steady state MHD models, with a mass source between 1.4×102 and 1.1×103 kg/s. After considering several configurations for the active atmospheric regions, we consider as most probable the main auroral oval, with associated mass source between 49.7±13.4 and 239.8±64.8 kg/s for an average auroral oval, and 10±4 and 49±23 kg/s for the specific auroral oval morphology found during this event. It is not clear how much of this mass is trapped within the magnetosphere and how much is lost to the solar wind.

AB - Studies of Saturn's magnetosphere with the Cassini mission have established the importance of Enceladus as the dominant mass source for Saturn's magnetosphere. It is well known that the ionosphere is an important mass source at Earth during periods of intense geomagnetic activity but lesser attention has been dedicated to study the ionospheric mass source at Saturn. In this paper we describe a case study of data from Saturn's magnetotail, when Cassini was located at ∼2200 hours Saturn local time at 36 RS from Saturn. During several entries into the magnetotail lobe, tailward-flowing cold electrons and a cold ion beam were observed directly adjacent to the plasma sheet and extending deeper into the lobe. The electrons and ions appear to be dispersed, dropping to lower energies with time. The composition of both the plasma sheet and lobe ions show very low fluxes (sometimes zero within measurement error) of water group ions. The magnetic field has a swept-forward configuration which is atypical for this region and the total magnetic field strength larger than expected at this distance from the planet. Ultraviolet auroral observations show a dawn brightening and upstream heliospheric models suggest that the magnetosphere is being compressed by a region of high solar wind ram pressure. We interpret this event as the observation of ionospheric outflow in Saturn's magnetotail. We estimate a number flux between 2.95±0.43×109 1.43±0.21×1010 cm-2 s-1, one or about two orders magnitude larger than suggested by steady state MHD models, with a mass source between 1.4×102 and 1.1×103 kg/s. After considering several configurations for the active atmospheric regions, we consider as most probable the main auroral oval, with associated mass source between 49.7±13.4 and 239.8±64.8 kg/s for an average auroral oval, and 10±4 and 49±23 kg/s for the specific auroral oval morphology found during this event. It is not clear how much of this mass is trapped within the magnetosphere and how much is lost to the solar wind.

U2 - 10.1002/2015JA021648

DO - 10.1002/2015JA021648

M3 - Journal article

VL - 121

SP - 338

EP - 357

JO - Journal of Geophysical Research: Space Physics

JF - Journal of Geophysical Research: Space Physics

SN - 2169-9402

IS - 1

ER -