On the Effect of Local Plasma Parameters on Interplanetary Nanodust Observations.

Abstract:

Dust particles provide an important fraction of the matter composing the interplanetary medium, their mass density at 1 AU being comparable to the one of the solar wind. Among them, dust grains of nanometer size-scale can be detected using radio and plasma wave instruments, because they move at roughly the solar wind speed. The high velocity impact of a dust particle generates a small crater on the spacecraft: the dust particle and the crater material are vaporized. This produces a plasma cloud whose associated electrical charge induces an electric pulse measured with radio and plasma instruments. Since their first detection in the interplanetary medium (Meyer-Vernet et al. 2009), nanodust particles have been routinely measured using STEREO/WAVES instrument (Zaslavsky et al. 2012, Le Chat et al. 2013). From the physical process at the origin of the voltage pulse (Pantellini et al 2013), an effect of the local plasma density is expected. We present the nanodust properties measured using STEREO/WAVES/Low Frequency Receiver (LFR) data between 2007 and 2014, and show the effect of the local plasma density on the measurement. We also, for the first time, present evidence of Coronal Mass Ejection effects on the nanodust flux at 1 AU.