In this section
@article{Lewis:2024:mnras/stae856,
author = {Lewis, ZM and Beth, A and Galand, M and Henri, P and Rubin, M and Stephenson, P},
doi = {mnras/stae856},
journal = {Monthly Notices of the Royal Astronomical Society},
pages = {66--81},
title = {Constraining ion transport in the diamagnetic cavity of comet 67P},
url = {http://dx.doi.org/10.1093/mnras/stae856},
volume = {530},
year = {2024}
}
TY - JOUR
AB - The European Space Agency Rosetta mission escorted comet 67P for a 2-yr section of its six and a half-year orbit around theSun. By perihelion in 2015 August, the neutral and plasma data obtained by the spacecraft instruments showed the comet hadtransitioned to a dynamic object with large-scale plasma structures and a rich ion environment. One such plasma structure isthe diamagnetic cavity: a magnetic field-free region formed by interaction between the unmagnetized cometary plasma andthe impinging solar wind. Within this region, unexpectedly high ion bulk velocities have been observed, thought to have beenaccelerated by an ambipolar electric field. We have developed a 1D numerical model of the cometary ionosphere to constrainthe impact of various electric field profiles on the ionospheric density profile and ion composition. In the model, we includethree ion species: H2O+, H3O+, and NH+4 . The latter, not previously considered in ionospheric models including acceleration, isproduced through the protonation of NH3 and only lost through ion–electron dissociative recombination, and thus particularlysensitive to the time-scale of plasma loss through transport. We also assess the importance of including momentum transferwhen assessing ion composition and densities in the presence of an electric field. By comparing simulated electron densities toRosetta Plasma Consortium data sets, we find that to recreate the plasma densities measured inside the diamagnetic cavity nearperihelion, the model requires an electric field proportional to r−1 of around 0.5–2 mV m−1 surface strength, leading to bulk ionspeeds at Rosetta of 1.2–3.0 km s−1.
AU - Lewis,ZM
AU - Beth,A
AU - Galand,M
AU - Henri,P
AU - Rubin,M
AU - Stephenson,P
DO - mnras/stae856
EP - 81
PY - 2024///
SN - 0035-8711
SP - 66
TI - Constraining ion transport in the diamagnetic cavity of comet 67P
T2 - Monthly Notices of the Royal Astronomical Society
UR - http://dx.doi.org/10.1093/mnras/stae856
UR - https://academic.oup.com/mnras/article/530/1/66/7634366
UR - http://hdl.handle.net/10044/1/114156
VL - 530
ER -