The interaction of a solar wind discontinuity with the backstreaming particles of the Earth’s ion foreshock can generate hot, tenuous plasma transients such as foreshock bubbles (FB) and hot flow anomalies (HFA). These transients are known to have strong effects on the magnetosphere, distorting the magnetopause (MP), either locally during HFAs or globally during FBs. However, previous studies on the global impact of FBs have not been able to determine whether the response stems directly from the transverse scale size of the phenomenon or its fast motion over the magnetosphere. Here we present the observation of an FB and its impact on the magnetosphere from different spacecraft scattered over the dayside magnetosphere. We are able to constrain the size of the transverse scale of an FB from direct observations to be about 10 $R_\mathrm{E}$. We further suggest that a combination of this scale and the motion of the FB over the MP is responsible for the previously reported global response of the dayside magnetosphere.

Since its launch in 2000, the Cluster fleet visited a vast domain of the circum-terrestrial environment, from upstream solar wind and distant tail, down to the plasmasphere, scanning in detail all magnetospheric regions during almost two solar cycles. This led to an unprecedented rich data collection of multi-point measurements which will be used for years to come to decipher the mechanisms of Solar-Terrestrial interactions. The large volume of the data gathered by Cluster requires special strategies to make efficient use of it. To address this issue we constructed a browsable database containing ULF waves and spacecraft formation parameters. Recently, we made this database accessible at http://plasma.spacescience.ro/cluster.html. Here we present the newly developed tool, discuss the methods used to derive the parameters and give practical examples.