Ionospheric effects of the magnetic storm on 18--22 August...

INTERNATIONAL JOURNAL OF GEOMAGNETISM AND AERONOMY VOL. 5, GI1007, doi:10.1029/2003GI000059, 2004

Ionospheric effects of the magnetic storm on 18-22 August 2003 according to the data of HF sounding of the artificial ionospheric turbulence

V. P. Uryadov¹, G. G. Vertogradov², V. G. Vertogradov², A. A. Ponyatov¹, and V. L. Frolov¹

¹Radiophysical Research Institute, Nizhny Novgorod, Russia
²Rostov on Don State University, Rostov on Don, Russia

Abstract

[1] The results of the experimental studies of the influence on the HF signals characteristics of the artificial ionospheric turbulence (AIT) created by the impact on the ionosphere of the powerful radioemission of the heating facilities SURA (Nizhny Novgorod region of Russia) are presented. The measurements were conducted on 18-22 August 2003 in the evening time (1600-2000 UT) at the linearly frequency modulated (LFM) sounding paths: Khabarovsk-Rostov on Don, Irkutsk-Rostov on Don, and Inskip (England)-Rostov on Don and also at the Moscow-Rostov on Don path by the reception of signals of the RVM precise time stations. It was found that at the presence of a strong sporadic E layer at the Irkutsk-SURA path, there appeared the conditions for the SW signal propagation through the upper ionosphere at the frequencies exceeding the maximum usable frequency of the standard hop-like propagation through the F region. The presence of these signals was detected by descending of radio waves from F region altitudes to the Rostov-on-Don reception point due to their scatter at artificial small-scale magnetically oriented irregularities. Using the measurements of the Doppler shift of the frequency of the signals scattered at AIT, ionospheric effects of the magnetic storm occurred in the period of the experiment were studied. It is shown that during the magnetic storm the electric field and irregularity drift velocity at F -region heights over the SURA facility reached values of ~8.6 mV m ^-1 and 186 m s ^-1, respectively, that is, the values typical for the high-latitude ionosphere. The relation of the quasiperiodic oscillations of the Doppler frequency of the scattered signal to propagation of magnetohydrodynamics waves excited during a magnetic storm is considered.

Received 23 December 2003; revised 18 May 2004; accepted 17 June 2004; published 28 July 2004.

Keywords: Artificial ionospheric turbulence; Heating facilities SURA; Ionospheric effects of the magnetic storm.

Index Terms: 2403 Ionosphere: Active experiments; 2471 Ionosphere: Plasma waves and instabilities; 2431 Ionosphere: Ionosphere/magnetosphere interactions.

Citation: Uryadov, V. P., G. G. Vertogradov, V. G. Vertogradov, A. A. Ponyatov, and V. L. Frolov (2004), Ionospheric effects of the magnetic storm on 18--22 August 2003 according to the data of HF sounding of the artificial ionospheric turbulence, Int. J. Geomagn. Aeron., 5, GI1007, doi:10.1029/2003GI000059.