In this section
@article{Lewis:2025:mnras/staf1162,
author = {Lewis, ZM and Stephenson, P and Beth, A and Galand, M and Kallio, E and Moeslinger, A},
doi = {mnras/staf1162},
journal = {Monthly Notices of the Royal Astronomical Society},
pages = {3590--3605},
title = {Cometary ion dynamics at 67P: a collisional test-particle approach with Rosetta data comparison},
url = {http://dx.doi.org/10.1093/mnras/staf1162},
volume = {541},
year = {2025}
}
TY - JOUR
AB - The Rosetta spacecraft escorted comet 67P/Churyumov–Gerasimenko for two years, gathering a rich and variable data set.Amongst the data from the Rosetta Plasma Consortium (RPC) suite of instruments are measurements of the total electron densityfrom the Mutual Impedance Probe (MIP) and Langmuir Probe (LAP). At low outgassing, the plasma density measurements canbe explained by a simple balance between the production through ionization and loss through transport. Ions are assumed totravel radially at the outflow speed of the neutral gas. Near perihelion, the assumptions of this field-free chemistry-free modelare no longer valid, and plasma density is overestimated. This can be explained by enhanced ion transport by an ambipolarelectric field inside the diamagnetic cavity, where the interplanetary magnetic field does not reach. In this study, we explore thetransition between these two regimes, at intermediate outgassing (5.4 × 1026 s−1), when the interaction between the cometaryand solar wind plasma influences the transport of the ions. We use a 3D collisional test-particle model, adapted from Stephensonet al. to model the cometary ions with input electric and magnetic fields from a hybrid simulation for 2.5–3 au. The total plasmadensity from this model is then compared to data from MIP/LAP and to the field-free chemistry-free model. In doing so, wehighlight the limitations of the hybrid approach and demonstrate the importance of modelling collisional cooling of the electronsto understand the ion dynamics close to the nucleus.
AU - Lewis,ZM
AU - Stephenson,P
AU - Beth,A
AU - Galand,M
AU - Kallio,E
AU - Moeslinger,A
DO - mnras/staf1162
EP - 3605
PY - 2025///
SN - 0035-8711
SP - 3590
TI - Cometary ion dynamics at 67P: a collisional test-particle approach with Rosetta data comparison
T2 - Monthly Notices of the Royal Astronomical Society
UR - http://dx.doi.org/10.1093/mnras/staf1162
UR - https://doi.org/10.1093/mnras/staf1162
VL - 541
ER -