Plasma characterization at comet 67P between 2 and 4 AU from the Sun with the RPC-MIP instrument

Gaëtan Wattieaux (1) , Pierre Henri (2, 3) , Nicolat Gilet (2) , Xavier Vallières (2) , Jan Deca (4, 5, 6)

1 LAPLACE-PRHE - Plasmas Réactifs Hors Equilibre
2 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
3 LAGRANGE - Joseph Louis LAGRANGE
4 LASP - Laboratory for Atmospheric and Space Physics [Boulder]
5 IMPACT - Institute for Modeling Plasma, Atmospheres and Cosmic Dust
6 PLANETO - LATMOS

The plasma of comet 67P/Churyumov Gerasimenko is analyzed based on the RPC-MIP mutual impedance probe data of the Rosetta mission. Numerical simulations of the RPC-MIP instrumental response considering two populations of electrons were t on experimental responses acquired from January to September 2016 to extract the electron densities and temperatures. A time-tracking of the plasma parameters was performed, leading to the identi cation of a cold and a warm population of electrons during the period of interest. The respective densities and temperatures lie in the ranges [100 ; 1000] cm−3 and [0.05 ; 0.3] eV for the cold electrons and in the ranges [50 ; 500] cm−3 and [2 ; 10] eV for the warm electrons. Warm electrons most of the time made up between 10% and 30% of the whole population, while the temperature ratio between warm and cold electrons lay mostly between 30 and 70 during the period we studied. The uctuation range of the plasma parameters, that is, the electron densities and temperatures, appears to have remained rather constant during the last nine months of the mission. We take the limitations of the instrument that are due to the experimental noise into account in our discussion of the results.

Domains: Sciences of the Universe [physics]

Gaëtan Wattieaux, Pierre Henri, Nicolat Gilet, Xavier Vallières, Jan Deca. Plasma characterization at comet 67P between 2 and 4 AU from the Sun with the RPC-MIP instrument. Astronomy and Astrophysics - A&A, 2020, 638, A124 (11 p.). ⟨10.1051/0004-6361/202037571⟩. ⟨insu-02610363⟩