Physics of auroral phenomena : proceedings of the 39th annual seminar, Apatity, 29 February-4 March, 2016 / [ed. board: N. V. Semenova, A. G. Yahnin]. - Апатиты : Издательство Кольского научного центра РАН, 2016. - 167 с. : ил., табл.

Experimental determination of the D-region ionosphere effective recombination coefficients found. Then from the times of the EC minima of the profiles (circles in Fig. 3) the temporary delays were received. Finally on the formula (4) ERC were calculated. Heights and values of effective recombination coefficients are specified in tabl. 1. For the solar eclipses on 11 August 1999, on 1 June 2011 and on 1 August 2008 the technique of receiving of ERC was similar. 5.2. Eclipse on 1 June 2011 The 1 June solar eclipse was partial one. Parameters of the partial eclipse at the place of observation: the beginning - at 8:33:49 UT, the maximum - at 9:23:17 UT, the end - at 10:12:37 UT; the value of the greatest phase of the eclipse was 0.598; the height of the Sun over the horizon at the time of the greatest phase of the eclipse was 1.1°. The geomagnetic situation was weakly disturbed. The two-dimensional picture of the EC distribution in the period of the eclipse is given in Fig. 4. Letters В, M and E mean the beginning, the maximum and the end of the eclipse, respectively. During the eclipse the polar night was, the Sun at the time of observation was practically on the horizon. Consideration of EC profiles on ionospheric heights have not revealed profiles, using which it would be possible to calculate effective recombination coefficients. 5.3. Eclipse of the 1 August 2008 In Tumanny the 1 August 2008 total solar eclipse was partial one: the beginning - at 8:48:10 UT, the maximum - at 9:54:08 UT, the end - at 10:59:28 UT; value of the greatest phase of the eclipse was 0.827; the height of the Sun over the horizon at the time of the greatest phase of the eclipse was 38.8°. The 1 August 2008 the geomagnetic situation was quiet. The two-dimensional picture of the electron concentration distribution in the period of the eclipse is given in Fig. 5. Letters В, M and E mean the beginning, the maximum and the end of the eclipse, respectively. All the possible electron concentration profiles were considered for calculation of effective recombination coefficients but only for several heights the ERC were received. The heights and values of the ERC are specified in tabl. 2. Figure 4. Electron concentration distribution, the solar eclipse on 1 June 2011 Figure 5. Electron concentration distribution, the solar eclipse on the 1 August 2008 Table 1. Effective recombination coefficients, the solar eclipse on 20 March 2015 Height, km Effective recombination coefficients, ernes'1 68 3.7-10‘s 67 4.2T0'5 66 5.0-1 O'5 65 5.5 10"5 5.4. Eclipse on the 1 August 1999 Table 2. Effective recombination coefficients, the solar The beginning of the eclipse in Tumanny was at T1 eclipse on the 1 August 2008________________________ = 9:57:43 UT. The greatest phase of the eclipse was Height, km Effective recombination coefficients, ernes’1 0.44 at Tm = 10:54:26 UT, the height of the Sun 78.5 6.6-10~6 over the horizon at the time of the greatest phase of 77 8.1 TO'6 the eclipse h was 35.1 °. The end of the eclipse was at 75.5 1.3-10* T4 = 11:50:17 UT. The geomagnetic situation in the 74 4.7-10'3 period of the eclipse was quiet. The two-dimensional electron concentration distribution is given in Fig. 6. Consideration of electron the concentration profiles on heights have not revealed profiles which could be used for calculating effective recombination coefficients. Figure 6. Electron concentration distribution, the solar eclipse on 6. C o n c lu sio n the 11 August 1999 Observation of the ionosphere during solar eclipses on 1 August 1999, on 1 August 2008, on 1 June 2011 and on 20 March 2015 on the Time, UT 90