Electromagnetic instabilities in solar wind interaction with dusty cometary plasmas

Dusty plasmas contain charged dust grains which are much more massive than protons and carry high negative charges due to preferential capture of electrons. Fluctuations in the grain charges due to capture or liberation of additional electrons and protons translate as momentum losses or gains, which can lead to wave damping or growth. Many authors have addressed the pickup of ions of cometary origin by the solar wind, partly due to relative streaming between cometary and solar wind ions which excites low-frequency electromagnetic turbulence. In the present work we include effects due to charged dust in cometary environments. We have investigated several frequency regimes: nonresonant below the cometary charged dust gyrofrequency (new and interesting but highly unlikely!), nonresonant below the cometary watergroup gyrofrequency and resonant with the cometary watergroup ions. For most parameter ranges either existing instabilities can be enhanced, showing that charged dust facilitates the cometary ion pickup by the solar wind, or new instabilities or damping mechanisms have been shown to exist.