Magnetopause pressure pulses as a source of localized field-aligned currents in the magnetosphere

Spatial structures exhibiting twisted magnetic fields and associated vortical flows have been observed on the terrestrial magnetopause where they are called flux transfer events (FTE's) and are generally thought to be signatures of bursty reconnection. However, it has recently been argued that many of the events can be interpreted as magnetopause responses to impulsive changes of solar wind dynamic pressure, an interpretation that does not require any magnetic reconnection. One might expect that it is possible to distinguish the two mechanisms by examining the signatures produced within the magnetosphere and in the ionosphere. Within the ionosphere, impulsive magnetic disturbances and traveling vortical flows have been interpreted as ground signatures associated with isolated FTE's. In this paper we use a simple model magnetosphere to demonstrate the qualitative features of magnetospheric and ionospheric responses to FTE-like compressional disturbances on the magnetopause. We show that many aspects of the magnetospheric and ionospheric responses also mimic features that have been interpreted as FTE signatures.