Estimation of Neutral Densities in the Thermosphere

Abstract

Ionospheric energy balance is studied with incoherent scatter radar measurements that allow the estimation of neutral density and temperature from a statistical inversion problem. This method has been successfully studied at low latitudes using data over several years to make a robust model. This has not been done within the high latitude auroral regions and there are many factors that can complicate energy balance studies in this area, such as effects of Joule heating of the plasma. To study the feasibility of this type of study at high latitudes, a comparison was made between a parameterisation by Nicolls et al. (2006), a parameterisation of the MSIS model atmosphere included in the MATLAB aerospace toolbox and the estimations directly from the MSIS model atmosphere. Measurements were taken with the EISCAT tristatic system in hopes to determine Joule heating, however this failed due to outside radio interference causing an insufficient number of tristatic observations and making the results too imprecise to be conclusive. An in-depth analysis of the parameterisations was still carried out to find errors and determine ways to improve the method and model for future.