Observation of a new type of low-frequency waves at comet 67P/Churyumov-Gerasimenko
2015 (English)In: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 33, no 8, 1031-1036 p.Article in journal (Refereed) Published
We report on magnetic field measurements made in the innermost coma of 67P/Churyumov-Gerasimenko in its low-activity state. Quasi-coherent, large-amplitude (delta B/B similar to 1), compressional magnetic field oscillations at similar to 40 mHz dominate the immediate plasma environment of the nucleus. This differs from previously studied cometary interaction regions where waves at the cometary ion gyro-frequencies are the main feature. Thus classical pickup-ion-driven instabilities are unable to explain the observations. We propose a cross-field current instability associated with newborn cometary ion currents as a possible source mechanism.
Place, publisher, year, edition, pages
2015. Vol. 33, no 8, 1031-1036 p.
Magnetospheric physics (plasma waves and instabilities, solar wind interactions with unmagnetized bodies), solar physics astrophysics and astronomy (magnetic fields)
Geophysics Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:uu:diva-264338DOI: 10.5194/angeo-33-1031-2015ISI: 000360651100010OAI: oai:DiVA.org:uu-264338DiVA: diva2:860888