Rights statement: This is the peer reviewed version of the following article: Jasinski, J. M., Arridge, C. S., Bader, A., Smith, A. W., Felici, M., Kinrade, J., et al. ( 2019). Saturn's open‐closed field line boundary: A Cassini electron survey at Saturn's magnetosphere. Journal of Geophysical Research: Space Physics, 124, 10018– 10035. doi: 10.1111/jpim.12206 which has been published in final form at https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JA027090 This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
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Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Saturn's open‐closed field line boundary
T2 - a Cassini electron survey at Saturn's magnetosphere
AU - Jasinski, Jamie M.
AU - Arridge, Chris
AU - Bader, Alexander
AU - Smith, Andrew
AU - Felici, Marianna
AU - Kinrade, Joe
AU - Coates, A.J.
AU - Jones, Geraint
AU - Nordheim, T.
AU - Gilbert, Lin
AU - Azari, Abigail
AU - Badman, Sarah
AU - Provan, G.
AU - Sergis, N.
AU - Murphy, Neil
N1 - This is the peer reviewed version of the following article: Jasinski, J. M., Arridge, C. S., Bader, A., Smith, A. W., Felici, M., Kinrade, J., et al. ( 2019). Saturn's open‐closed field line boundary: A Cassini electron survey at Saturn's magnetosphere. Journal of Geophysical Research: Space Physics, 124, 10018– 10035. doi: 10.1111/jpim.12206 which has been published in final form at https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JA027090 This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
PY - 2019/12/1
Y1 - 2019/12/1
N2 - We investigate the average configuration and structure of Saturn's magnetosphere in the nightside equatorial and high‐latitude regions. Electron data from the Cassini Plasma Spectrometer's Electron Spectrometer (CAPS‐ELS) is processed to produce a signal‐to‐noise ratio for the entire CAPS‐ELS time of operation at Saturn's magnetosphere. We investigate where the signal‐to‐noise ratio falls below 1, to identify regions in the magnetosphere where there is a significant depletion in the electron content. In the nightside equatorial region we use this to find that the most planetward reconnection x‐line location is at 20 – 25 RS downtail from the planet in the midnight to dawn sector. We also find an equatorial dawn‐dusk asymmetry at a radial distance of >20 RS which may indicate the presence of plasma depleted flux tubes returning to the dayside after reconnection in the tail. Furthermore, we find that the high‐latitude magnetosphere is predominantly in a state of constant plasma depletion and located on open field lines. We map the region of high‐latitude magnetosphere that is depleted of electrons to the polar cap to estimate the size and open flux content within the polar caps. The mean open flux content for the northern and southern polar caps are found to be 25±5 and 32±5 GWb, respectively. The average location of the open‐closed field boundary is found at invariant colatitudes of 12.7±0.6° and 14.5±0.6°. The northern boundary is modulated by planetary period oscillations more than the southern boundary.
AB - We investigate the average configuration and structure of Saturn's magnetosphere in the nightside equatorial and high‐latitude regions. Electron data from the Cassini Plasma Spectrometer's Electron Spectrometer (CAPS‐ELS) is processed to produce a signal‐to‐noise ratio for the entire CAPS‐ELS time of operation at Saturn's magnetosphere. We investigate where the signal‐to‐noise ratio falls below 1, to identify regions in the magnetosphere where there is a significant depletion in the electron content. In the nightside equatorial region we use this to find that the most planetward reconnection x‐line location is at 20 – 25 RS downtail from the planet in the midnight to dawn sector. We also find an equatorial dawn‐dusk asymmetry at a radial distance of >20 RS which may indicate the presence of plasma depleted flux tubes returning to the dayside after reconnection in the tail. Furthermore, we find that the high‐latitude magnetosphere is predominantly in a state of constant plasma depletion and located on open field lines. We map the region of high‐latitude magnetosphere that is depleted of electrons to the polar cap to estimate the size and open flux content within the polar caps. The mean open flux content for the northern and southern polar caps are found to be 25±5 and 32±5 GWb, respectively. The average location of the open‐closed field boundary is found at invariant colatitudes of 12.7±0.6° and 14.5±0.6°. The northern boundary is modulated by planetary period oscillations more than the southern boundary.
U2 - 10.1029/2019JA027090
DO - 10.1029/2019JA027090
M3 - Journal article
VL - 124
SP - 10018
EP - 10035
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
SN - 2169-9402
IS - 12
ER -