Effects of disturbances on low orbit ionospheric electric field satellite measurements

Low-orbit satellites are located at altitudes below 2,000 kilometers of the Earth’s atmosphere and are devoted to various purposes, including communication, Earth observation, navigation and positioning, and measurements of different parameters such as density, temperature, and electric field. The latter is critical for space weather because of its key role in magnetosphere- ionosphere coupling, atmospheric dynamics and can be used as a precursor for strong natural events (storms, earthquakes, etc.). However, the accuracy of ionospheric electric field measurements depends on several factors such as vertical ionospheric density of different species, onboard satellite instruments, and external factors (solar wind, radiation, etc.). In the present study, we used data from the low orbit DEMETER satellite to obtain ambient ionospheric electric field by measuring the effective field, which is subject to the effect of the induced field due to satellite motion. This field is also subject to disturbance caused by natural events and shadows resulting from probes not being in the same condition regarding solar flux. For this purpose, a double probe technique is used, in which the measured electric field and the induced field are separated. Different key parameters were obtained to study the induced field variations, which in certain circumstances can overshadow the ambient (natural) field.