Bridging the gap between ground- and space-based investigations of magnetosphere–ionosphere coupling processes

Until recently spacecraft investigations of dynamic magnetospheric processes have occurred independently from those undertaken using ground-based active radar observations of the ionospheric signatures associated with these phenomena. This paper will review recent experiments combining these data sets in order to study magnetosphere–ionosphere coupling. The techniques discussed will include: (i) the investigation of ULF waves generated by wave–particle interactions in the inner magnetosphere and subsequent ring current energy dissipation in the ionosphere; (ii) studies of the high latitude acceleration region responsible for the formation of aurora and (iii) the tagging of flux tubes in order to increase the confidence that ground and space observations are truly conjugate. In each case the satellite observations will be discussed in the context of coherent HF and incoherent UHF radar measurements as well as high power radio heating experiments that can be employed to simulate naturally occurring processes.