Investigating Ionospheric Spread-F Growth Rates using Ion-neutral and Electron-neutral Collision Frequencies

Equatorial and midlatitude spread-F (ESF and MSF) are regions of reduced plasma density in the ionosphere that disrupt communication and navigation systems. These phenomena are commonly attributed to the Rayleigh-Taylor (RT) instability at equatorial latitudes and the Perkins instability at midlatitudes. Key factors influencing the growth rates of these plasma instabilities include ion-neutral collision frequency, plasma electron density, and the density gradient [1]. This paper investigates the effects of these factors on the growth rates of the RT and Perkins instabilities, using data from the STORMS sounding rocket mission, launched from Wallops Island, Virginia, on October 30, 2007. The study incorporates data from the NRLMSIS and IRI models, available through the NASA CCMC website. The STORMS impedance magnitude data is fitted using the Balmain (1968) impedance model to obtain effective electron-neutral collision frequencies, following the formulae outlined in Smith and klenzing (2022) [2]. The effective plasma electron density is derived from the STORMS impedance phase data. These parameters, along with the NRLMSIS and IRI model data, are used to calculate effective ion-neutral collision frequencies. The ESF and MSF growth rates are then computed as a function of altitude during the time of the mission.