Prompt GPS TEC response to magnetospheric compression

Abstract

A new type of total electron content (TEC) variation was observed when an interplanetary shock impacted on the Earth's magnetosphere on 17 March 2015. With hundreds of ground‐based Global Positioning System (GPS) receivers, instantaneous TEC impulses were detected in the signals from four GPS satellites cruising in the dayside equatorial magnetosphere. Despite the small amplitude (0.3 TECU), the impulses were synchronously registered by receivers spreading from low to middle latitudes on the ground; they lasted for several minutes, during which period the interplanetary magnetic field (IMF) kept northward. The TEC impulses therefore discriminate themselves from usual traveling ionospheric disturbances and exclude possible effects from the southward IMF‐driven magnetic storm. We suggest that the TEC variation is caused by shock‐induced magnetospheric compression, which moves plasma earthward in the dayside plasmasphere. As a result, some plasma outside of GPS orbit (4.2 RE) is moved to the inside and contributes to the plasma content traversed by GPS raypath. The GPS TEC technique thus exhibits an unprecedented capability to capture small tremor of the magnetosphere, and with the dense receiver network on the ground it can be a feasible tool for remote sensing of the plasma dynamics around 4.2 RE.

Meso-Scale Electrodynamic Coupling of the Earth Magnetosphere-Ionosphere System

“…They found similar responses as in measurements but the magnitude of the responses is underestimated. Other studies also reported simultaneous ionospheric TEC modulation in response to the sudden compression of the magnetosphere (Hao et al 2017), but the observed enhancement of TEC was suggested to be resulted from the compression of plasmasphere instead of ionosphere.…”

Chinese ionospheric investigations in 2016–2017

“…Plasma moving from outside of GPS orbit (4.2 R E ) to inside contributes to the plasma content traversed by GPS ray path. The GPS TEC technique thus exhibits an unprecedented capability to sense plasma dynamics in the magnetosphere remotely (Hao YQ et al, 2017).…”

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

“…事件期间, Hao等人 [9] [14,15] , 以及低能的电子 和质子朝向地球的漂移 [16~18] . 这些局地探测从磁场、 电场、能量粒子的运动等角度描述了磁层被压缩的过 程 , 但 局 限 是 这 些 卫 星 多 运 行 于 地 球 同 步 轨 道 (36000 km高度), 即处于等离子体层以外.…”