Disturbed Flows in the Inner Solar Wind and Near Earth’s Orbit

Abstract

Coronal mass ejections from active regions on the Sun can be observed as series of individual events separated in time in the inner solar wind and near-Earth plasma. To find such events we have analyzed experimental data of dual-frequency solar wind radio sounding by the Rosetta and Mars Express spacecraft. The cycles of experiments performed in 2010 and 2011 measured the frequency fluctuations of X- and S-band signals. The temporal variations in the level of frequency fluctuations measured in the inner solar wind have been compared with the time variations in average plasma parameters recorded near Earth’s orbit. Since radio-sounding cycles were sufficiently long, we have managed to record events where significant amplifications of frequency fluctuations in the inner solar wind and increases in the plasma concentration near Earth’s orbit are associated with flare processes in the same active region on the Sun. Here, the amplifications of frequency fluctuations on the east limb occur earlier than near Earth’s orbit, and those on the west limb occur later. The time shift for the west limb turns out to be less than for the east limb. The sign of the time shift and the ratios between its numerical values depend on active region displacement relative to the central meridian due to the rotation of the Sun.