Analysis of sweeping impedance probe measurements in the F-layer of the ionosphere during the occurrence of a mid-latitude spread F event

Plasma Impedance Probes (PIP) are AC instruments that are used to measure and observe resonances and damping features in plasmas. These probes are typically flown on sounding rocket missions studying ionosphere plasma physics. In this work we present a combined circuit—empirical model for the frequency dependent impedance of a monopole probe on a sounding rocket payload that traverses multiple ionospheric layers. The purpose of this model is to resolve some difficulties encountered when interpreting and analyzing PIP measurements made at the higher altitudes during the Tropical STORMS sounding rocket launched from Wallops Island, Virginia, in 2007. In an earlier work (Spencer & Patra, 2015, https://doi.org/10.1002/2015rs005697), we identified the presence of anomalous damping in the measurements above 260 km. Here, we introduce a more detailed model of the plasma probe interaction to explain these observations. The new model incorporates the effect of a sheath, and some additional parallel conductivity elements that dampen the observed impedance in the F-layer of the ionosphere. We show that by accounting for the presence and gradual impact of the parallel conductance elements, the PIP data can be accurately analyzed and interpreted. We hypothesize that secondary electrons with higher mobilities may contribute to the observed effects, and propose future investigations that may be conducted to further understand the observations.