Mass loading at 67P/Churyumov‐Gerasimenko: A case study

• Published in: Geophysical research letters 2016-02, Vol.43 (4), p.1411-1418
• Main Authors: Behar, E., Nilsson, H., Wieser, G. Stenberg, Nemeth, Z., Broiles, T. W., Richter, I.
• Format: Article
• Language: English
• Subjects: 67P/CG; Astrophysics; Atmosfärsvetenskap; Atmosphere; Atmospheric science; Case studies; comet; Comet nuclei; Comets; Correlation; Direction; Distance; Dynamic tests; Dynamics; Electric field; Electric fields; Evolution; Ion dynamics; Ions; Loads (forces); Magnetic field; Magnetic fields; Mass; mass loading; Nuclei; Nuclei (nuclear physics); Nucleus; Polarization; Rosetta; Solar wind; Solar wind ions; Stellar mass; Sun; Theories; Wind power generation
• ISSN: 0094-8276; 1944-8007; 1944-8007
• DOI: 10.1002/2015GL067436

We study the dynamics of the interaction between the solar wind ions and a partially ionized atmosphere around a comet, at a distance of 2.88 AU from the Sun during a period of low nucleus activity. Comparing particle data and magnetic field data for a case study, we highlight the prime role of the solar wind electric field in the cometary ion dynamics. Cometary ion and solar wind proton flow directions evolve in a correlated manner, as expected from the theory of mass loading. We find that the main component of the accelerated cometary ion flow direction is along the antisunward direction and not along the convective electric field direction. This is interpreted as the effect of an antisunward polarization electric field adding up to the solar wind convective electric field. Key Points Prime role of the SW electric field in the cometary ion dynamics, through mass loading, at 2.88 AU The cometary ion flow direction has a main antisunward component We find an indication for an antisunward polarization electric field developing in the coma