Characterization of the active current system around the TSS-IR satellite through magnetic field measurements taken by the Tethered Magnetometer instrument

In this paper we present the measurements and interpretations of the Tethered Magnetometer (TEMAG) experiment flown on the Tethered Satellite Mission Reflight TSS-IR. Data were taken during the active operating phase when current steps of variable amplitude were injected along the electrically conducting tether. The magnetic field shows clear signatures in the components and amplitude, dependent upon the orientation of the magnetometer boom with respect to the spacecraft ram velocity vector. In the eight events studied, current effects could be observed in the magnetic field data only when the boom was pointing toward the ram side hemisphere of the satellite. The picture emerging from the observed results suggests the formation of a current sheet on the ram side, possibly associated with the aerodynamic shock and compression of the geomagnetic field ahead of the satellite. Although the limited data do not allow full description of the phenomenology, they place important observational constraints on any theoretical model.