Large-scale ionospheric density enhancements are frequently observed during geomagnetic storms. The enhancements could be the positive ionospheric storm at low-and mid-latitudes (e.g., Appleton & Ingram, 1935;Rajaram, 1977), or the storm enhanced density (SED) at mid-and high-latitudes. The SED terminology was first introduced by J. C. Foster (1993), to describe a stream-like structure of the enhanced plasma density spanning from its dusk-sector source at the subauroral region to the noontime cusp during the initial stage of the geomagnetic storm, that is, sunward and upward convecting cold plasma (Foster
The Swarm in situ Ne and Te measurements are used for the first time to investigate the plasma irregularities inside the MIT. The auroral particle precipitations dominate the dayside MIT region irregularities. The temperature gradient drift instability contributes mostly to the nightside MIT region irregularities.
An important aspect of the ionospheric behaviors during geomagnetic storms is the occurrence of various kinds of intermediate-scale plasma density structures at different latitudinal sectors. A brief list of those structures includes the tongue of ionization (e.g.,
In this study, we perform the first comprehensive comparison of ion density (Ni) in the topside ionosphere measured by the Langmuir probe (LP) and faceplate (FP) of the thermal ion imager on board Swarm satellites. Our results show a systematic difference between the LP and FP derived Ni values, and the systematic difference shows prominent dependences on solar flux, local time, and season. Although both Ni datasets show generally good linear regression with electron density (Ne) measurements from the incoherent scatter radar (ISR) located at Jicamarca, the Ni derived from LP shows an additional dependence on the solar flux, while such a dependence cannot be seen in the FP‐derived Ni. We suggest that the solar flux dependence of LP‐derived Ni is related to the ion compositions change at Swarm altitude, which has not been properly accounted for in the LP processing algorithm. More light ions (e.g., H+), diffusing down from the plasmasphere to the Swarm altitude, seem to cause the overestimation of Ni from LP during low solar activity. A linear relation between the Swarm LP‐derived Ni and ISR Ne is derived, and such a function is recommended to be implemented into further updates of the Swarm LP plasma density data.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.