Physics of auroral phenomena : proceedings of the 33rd Annual seminar, Apatity, 02 - 05 March, 2010 / [ed.: A.G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2011. - 206 с. : ил.

I. Shagimuratov al al. Results o f measurements and the analysis A typical example of the behavior of the amplitude reflection and the electron density in the lower ionosphere during the registration PMSE is shown in Figure 1. A0,AX, m V ; Ne, cm *3 Fig. 1. Time-altitude dependence of the amplitude reflections of the ordinary ( A 0) and extraordinary (Ax) waves and Ne(h) -profile of electron density. It is visible that the intense reflections of medium radiowaves are formed at altitudes 84-87 km near the cold summer mesopause. A characteristic feature of the observed reflections is that they come from areas with lower mesospheric electron density. According to our estimates, reducing the electron density associated with the appearance of PMSE, can range from 2 to 6 times. To clarify the causes of such low density of electrons was studied the effect o f atomic oxygen on the altitudinal distribution o f different types of ions and the electron density. The results of model calculations for electrons in the conditions of a quiet ionosphere and during the intrusion of solar protons are presented in Figure 2. The solid line in the figure on the left shows the profile of the electron density, measured by incoherent scattering (IS). Electron density, cnv3 Electron density, c n r 3 Fig. 2. To determine the influence of atomic oxygen on the electron density distribution in the lower ionosphere. 1 - to small neutral components of the mesosphere in quiet conditions, 2 - in disturbed conditions. Calculations show that a marked decrease in electron density up to 2-3 times by reducing the concentration of atomic oxygen in the 5-10 times are only during the intrusion of solar protons. In quiet conditions, our model could not explain the structural features of the D-region ionosphere with the appearance o f PMSE. To explain the observed dependence was suggested by the hypothesis o f an essential role of dusty plasmas in D- region. In this case, you must accept that the recombination of positive and negative charges mainly occurs on dust particles. It is known, that because o f the higher electron mobility compared with positive ions, neutral particles are taking a negative charge. On these negatively charged dust particles occurs the recombination of positive ions. With the account, the plasma recombination on dust particles, balance equation can be written as follows: = q - a . eNeN +- a a N eNci - $ N e +yN~ - 8 eN eN d, -27.07.1999 UT, hr 156