Meteor Smoke Particles in the D-Region Ionosphere - Implications from the Sic Model on Ions and Other Neutrals

Abstract:

Meteor smoke particles (MSP) play an important role in the aeronomy of the middle atmosphere as shown by satellite, groundbased and in-situ measurements. Especially the MSPs influence on the D-region charge balance has been studied recently by rocket borne measurements and a simplified ionospheric model. Here, the influence of MSP on the ionosphere and also the neutral atmosphere is studied within the complete chemistry of the Sodankylä Ion and Neutral Chemistry Model (SIC). The SIC model is a time dependent ionospheric model with 43 positive ion species, 29 negative ion species and 15 neutral species. In addition the output of an aerosol microphysics model is used to initialize the MSP distribution. The chemistry of these ions and neutrals is realised through more than 300 different reactions, e.g. photoionization, electron-ion recombination and ion-neutral interaction. The interaction between MSP and the charged components of the SIC model is expressed by MSP size dependent capture rates. By implementing MSP as new components into the reaction scheme of the SIC-model we can identify their influence on both, the D-region ionosphere and the neutral mesosphere. This influence is studied during polar night were electrons are effectively captured between 80 and 100 km. This lack of electrons causes an increase of positive ion numberdensity due to reduced electron-ion recombination. We concentrate in this paper on the changes in the negative and positive ion chemistry due to the presence of MSP.