Using GNSS TEC technique to observe compression of the plasmasphere by an interplanetary shock

An interplanetary shock impinged on the Earth’s magnetosphere on 17 March 2015, and caused instant change of total electron content (TEC) measured by ground-based global positioning system (GPS) receivers. Hao et al. (2017) attributed the sudden TEC variation to magnetospheric compression by the shock, and in this paper we follow to examine the process by incorporating high time-resolution (1 s) TEC data from some GPS receivers as well as TEC measurements from BeiDou Navigation Satellite System. These observations add new understandings to the reaction of magnetosphere to a strong shock. The compression drives plasma in dayside magnetosphere to move earthward, and the contraction of the Earth’s magnetic field will make plasma concentrate near the equatorial plane. The scenario involves dynamics of the plasmasphere where the plasma is dense enough to contribute to the variations of both GPS and Beidou TEC. In addition, we also inspect TEC measured onboard several low Earth orbit satellites, but no significant change is identified possibly due to inappropriate satellite position. The above TEC measurements, known collectively as global navigation satellite system (GNSS) TEC techniques, exhibit an unprecedented capability of remote sensing and will hopefully provide new insight into the dynamics of magnetosphere.