Neutral_ion_v1.0

Version of the 2-fluid model used to examine both ions and neutrals at Mars. This code fits to the identified wave perturbations (density
pertrubation amplitude ratio and phase offset) for 3 gas species - CO2, N2 and O as 2-separate 2-fluid fits. It returns the best fit gravity wave parameters and an estimation of the goodness of fit.
The code is derived from Cui, J., Y. Lian, and I. C. F. Müller-Wodarg (2013), Compositional effects in Titan’s thermospheric gravity waves,Geophys. Res. Lett., 40, 43–47, doi:10.1029/2012GL054621 and adapted to Mars by England, S. L., G. Liu, E. Yiğit, P. R. Mahaffy, M. Elrod, M. Benna, H. Nakagawa, N. Terada, and B. Jakosky (2017), MAVEN NGIMS observations of atmospheric gravity
waves in the Martian thermosphere, J. Geophys. Res. Space Physics, 122, doi:10.1002/ 2016JA023475.