In situ spacecraft missions are powerful assets to study processes that
occur in space plasmas. One of their main limitations, however, is
extrapolating such local measurements to the global scales of the
system. To overcome this problem at least partially, multi-point
measurements can be used. There are several multi-spacecraft missions
currently operating in the Earth’s magnetosphere, and the simultaneous
use of the data collected by them provides new insights into the
large-scale properties and evolution of magnetospheric plasma processes.
In this work, we focus on studying the Earth’s magnetopause using a
conjunction between the MMS and Cluster fleets, when both missions
skimmed the magnetopause for several hours at distant locations during
radial IMF conditions. The observed magnetopause positions as a function
of the evolving solar wind conditions and compared to model predictions
of the magnetopause. We observe an inflation of the magnetosphere (˜0.7
RE), consistent with magnetosheath pressure decrease
during radial IMF conditions, which is less pronounced on the flank
(< 0.2 RE). There is observational evidence of
magnetic reconnection in the subsolar region for the whole encounter,
and in the dusk flank for the last portion of the encounter, suggesting
that reconnection was extending more than 15 RE.
However, reconnection jets were not always observed, suggesting that
reconnection was patchy, intermittent or both. Shear flows reduce the
reconnection rate up to ˜30% in the dusk flank according to
predictions, and the plasma ß enhancement in the magnetosheath during
radial IMF favors reconnection suppression by the diamagnetic drift.