Modelling of the ion composition in the lower high-latitude ionosphere during solar proton precipitation

Osepian, A.1, Kirkwood, S.2, Dalin, P.2 and Tereschenko, V.1

1 Polar Geophysical Institute, Murmansk, Russia
2 Swedish Institute of Space Physics, Kiruna, Sweden

The height profiles of the main positive ions (O2+ and NO+ intermediate cluster ions of the form of O2+(X) and NO+(X), combined into a family Cluster1+, proton hydrated family Cluster2+) and negative ions (O2, O-, NO3-, CO3-), electron density and effective recombination coefficient are calculated for quiet conditions and at the time of the solar proton event (SPE) on 17 January 2005 based, on a theoretical ionization-recombination model of the D-region. The different height profiles of the minor neutral constituents (NO, O, O3), which are the tracers for quiet and SPE conditions, are incorporated into the theoretical model as input parameters. Since the atomic oxygen plays a dominant role in processes controlling the ionization balance, the experimental data on the electron density obtained with the incoherent scatter technique as well as with partial reflection technique are used as a criterion for choosing the O-profile during SPE from available theoretical O-models at mesospheric altitudes. Variations of the ionic composition, associated with extra ionization by the solar proton fluxes, and variations of the minor neutral constituents during the SPE are considered.

This work is partly supported by the RFFI grant No. 07-05-00012.