Solar Wind Modulation of Jupiter Dust Stream Detection

Abstract

During late 2002 and mid 2005, the Ulysses spacecraft approached Jupiter ( 0.8 AU at its closest distance) and detected 28 new Jovian dust particle streams. The tiny positively charged dust grains ( 10 nm) in the streams are accelerated away from Jupiter by its corotational electric field to very high speeds (greater than 200 km s^{-1}). Data indicate that, once outside the Jovian magnetosphere, dust grains are under the influence of the interplanetary magnetic field (IMF) and some characteristics of this field are observed on the dust streams. On the whole, every detected dust stream is preceded by a high IMF event that in most cases corresponds to corotating interaction regions (CIRs) and in few cases to coronal mass ejections (CMEs). The dust stream duration matches roughly the duration of these previous events indicating a confinement of the dust stream particles in the compressed regions of the interplanetary plasma. Additionally, most dust stream peaks and the precedent high IMF events peaks seem to be separated by an interval roughly similar to the time needed by a dust particle to travel from the source to the spacecraft's detector.