Physics of auroral phenomena : proceedings of the 35th Annual seminar, Apatity, 28 Februaru – 02 March, 2012 / [ed. board: A. G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2012. - 187 с. : ил., табл.

THE DISPLAYING OF HELIOGEOPHYSICAL DISTURBANCE IN MID-LATITUDE IONOSPHERIC INDEX 0.M . Barkhatova1’2, I.A. Dodonova1, N.V. Kosolapova2 1Nizhniy Novgorod State University o f Architecture and Civil Engineering, Nizhniy Novgorod, Russia 2Nizhniy Novgorod State Pedagogical University, Nizhniy Novgorod[ Russia Abstract. The connection between Solar-magnetospheric parameters with ionospheric index IAI was established and the estimation of their contribution extent to the index value was conducted. The key parameters are considered: AE index, the values of the geomagnetic field horizontal component, the values of the long-wave X-ray radiation in the range o f 1-8 A. The degree of each parameter contribution and their total contribution (40%) in the overall level of ionospheric disturbance was evaluated. A neural network operative diagnostics technique of the mid-latitude ionosphere with account of the heliogeophysical activity level was developed and the most efficient neural network input parameters were established. Achieve maximum efficiency of index values IAI reconstruction was 75%. Introduction Currently it has been established that the level of midlatitude ionosphere disturbance has influence of Solar- magnetospheric activity. A number of recent works dedicated to finding the most effective parameters that significantly disturbed the ionospheric ionization layers. In [Liu et al., 2007] noted that the ionospheric disturbance is dependent on the Solar cycle, which results in almost linear electron density increase of the ionosphere at middle and low latitudes from minimum to maximum eleven-year cycle. A number of other studies found the dependence of the critical frequency of the ionospheric layer F2 on the sunspot number, the variations of Solar radio emission at a wavelength of 10.7 cm (F10.7) and ultraviolet (EUV) [Balan et al. 1993, 1996; Liu et al., 2003 ; Lastovicka et al., 2008]. In [Liu et al., 2007], for example, pointed out that the plasma density at the top of the daytime ionosphere depends linearly on the index F10.7 and has a clear non-linear dependence of EUV. The rate of ionosphere concentration changes increases with increasing EUV. In addition, the magnetospheric parameters may affect on the density variations of ionospheric ionization. In [Barkhatova et al, 2009], for example, revealed the dependence of the critical frequency of the ionospheric layer F2 from index SYM-D which characterizes the D-component of symmetric part o f low-latitude field disturbance. In [Zubova and Namgaladze, 2011] it is marked ionospheric response to the April, 2002 geomagnetic disturbances by the electron density decrease in 2 and more times. The effect was accompanied by the ion and electron temperatures increase. This study assessed the influence degree of Solar-magnetospheric parameters for the index IAI, developed earlier [Barkhatova et al., 2011; Barkhatov and Barkhatova, 2012] based on the classification of variations F2 layer critical frequencies. The contribution of each parameter in the general level of the midlatitude ionospheric disturbances is revealed. Based on the established results, neural network method for reconstruction of IAI was made with maximum efficiency reached 75%. 1. The data used and processed The estimation of ionospheric disturbance level was conducted on the data of mid-latitude vertical sounding station Moscow (55° N, 37° E) for the full cycle of Solar activity from 1975 to 1986. The disturbance level of auroral region described by AE index, the geomagnetic activity level was assessed using the values of geomagnetic field horizontal component (MF) and the current level of solar activity - using the values of the X-ray (XL) in the range of 1-8 A. The latter parameter was chosen for reasons of its close association with the values of EUV. The data used resolution was 1 hour. Based on the original values of the critical frequencies were calculated ionospheric index IAI values. The method of creating the index is described in [Barkhatova et al., 2011; Barkhatov and Barkhatova, 2012]. Analysis of IAI values dependence from marked above Solar and geophysical parameters required indexing the actual values of these parameters. For AE index, whose values are non-negative, was leaded in five classes corresponding to a different level of auroral disturbance. Each of the derived classes was assigned a value from 0 to 4 by analogy with IAI index. The AE index boundary values for these classes are based on its values analysis at the minimum (1975) and maximum (1982) considered Solar cycle. Note that the auroral disturbances with the AE index value less than 500 nT accepted background. The rest of disturbances were arbitrarily divided into classes with each new class of consistent increase in the AE index values for 300 nT. The result was a new parameter CAE (classificated AE) whose values are subsequently compared with IAI index values. A similar scheme has been classified the values of the long-wavelength X-rays (XL). To select a background level the mean value of the sequence data was subtracted. This resulted to small negative values in the sequence of cleared XL, which is taken *P h y sics o f A uroral P h en om en a’’, Proc. XXXV A n n u al Sem inar, A p a tity, p p . 103 -1 0 6 , 2 0 1 2 © Kola Science Centre, Russian Academy o f Science, 2012 Polar Geophysical Institute 103