Imperial College London
Alternate

ProfessorMarinaGaland

Faculty of Natural Sciences, Department of Physics

Professor in Planetary Science
 
 
 
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Contact

 

m.galand Website

 
 
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Location

 

Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Heritier:2018:0004-6361/201832881,
author = {Heritier, K and Galand, M and Henri, P and Johansson, FL and Beth, A and Eriksson, AI and Vallières, X and Altwegg, K and Burch, JL and Carr, C and Ducrot, E and Hajra, R and Rubin, M},
doi = {0004-6361/201832881},
journal = {Astronomy and Astrophysics},
title = {Plasma source and loss at comet 67P during the Rosetta mission},
url = {http://dx.doi.org/10.1051/0004-6361/201832881},
volume = {618},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Context.The Rosetta spacecraft provided us with a unique opportunity to study comet 67P/Churyumov-Gerasimenko from a closeperspective and over a two-year time period. Comet 67P is a weakly active comet. It was therefore unexpected to find an active anddynamic ionosphere where the cometary ions were largely dominant over the solar wind ions, even at large heliocentric distances.Aims.Our goal is to understand the different drivers of the cometary ionosphere and assess their variability over time and over thedifferent conditions encountered by the comet during the Rosetta mission.Methods.We  used  a  multi-instrument  data-based  ionospheric  model  to  compute  the  total  ion  number  density  at  the  position  ofRosetta. In-situ measurements from the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) and the Rosetta PlasmaConsortium (RPC)–Ion and Electron Sensor (IES), together with the RPC–LAngmuir Probe instrument (LAP) were used to computethe local ion total number density. The results are compared to the electron densities measured by RPC–Mutual Impedance Probe(MIP) and RPC–LAP.Results.We  were  able  to  disentangle  the  physical  processes  responsible  for  the  formation  of  the  cometary  ions  throughout  thetwo-year escort phase and we evaluated their respective magnitudes. The main processes are photo-ionization and electron-impactionization. The latter is a significant source of ionization at large heliocentric distance (>2 au) and was predominant during the lastfour months of the mission. The ionosphere was occasionally subject to singular solar events, temporarily increasing the ambientenergetic electron population. Solar photons were the main ionizer near perihelion at 1.3 au from the Sun, during summer 2015.
AU  - Heritier,K
AU  - Galand,M
AU  - Henri,P
AU  - Johansson,FL
AU  - Beth,A
AU  - Eriksson,AI
AU  - Vallières,X
AU  - Altwegg,K
AU  - Burch,JL
AU  - Carr,C
AU  - Ducrot,E
AU  - Hajra,R
AU  - Rubin,M
DO  - 0004-6361/201832881
PY  - 2018///
SN  - 0004-6361
TI  - Plasma source and loss at comet 67P during the Rosetta mission
T2  - Astronomy and Astrophysics
UR  - http://dx.doi.org/10.1051/0004-6361/201832881
UR  - http://hdl.handle.net/10044/1/61485
VL  - 618
ER  -
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