Ilya V. Zhivetiev

MHD nature of ionospheric wave packets generated by the solar terminator

The morphology of medium-scale traveling wave packets is for the first time presented based on the total electron content (TEC), measured at the global network of GPS receivers (up to 1500 stations) during the long period (from 1998 to 2007) and at the GPS/GEONET dense Japan network (1220 stations) in 2008—2009. In the time domain, these packets are chains of narrowband TEC variations (trains) with a duration of about 1—2 h, a total duration of up to 6 h, and a variation period of 10—30 min. In the winter Northern Hemisphere, traveling wave packets are observed mostly 3 h after the passage of the morning solar terminator. In the equinox they appear after the passage of the solar terminator without a pronounced delay or advance. In summer traveling wave packets are registered 1.5—2 h before the appearance of the evening solar terminator at the observation point when the solar terminator passes in the magnetically conjugate region. The spatial structure of traveling wave packets is characterized by a high degree of anisotropy and coherence at a distance larger than ten wavelengths (the wavelength is 100—300 km). A high quality of the oscillatory system and synchronization with the appearance of the solar terminator at the observation point and in the magnetically conjugate region indicate that the generation of traveling wave packets by the solar terminator is of the MHD nature. Our results for the first time experimentally confirm the hypothesis that the solar terminator generates ion sound waves, proposed by Huba et al. [2000b].

Ionosphere and magnetosphere disturbance impact on operation slips of Global navigation satellite systems at mid- and high-latitudes

We studied the dynamics of the GLONASS and GPS radio physical signal slips, as well as the slips in determining the total electron content (TEC) at the stations in the mid- and high-latitude regions under different geophysical conditions over 2014 Nov - 2015 Jul. At high latitudes, the pseudo-range P1 measurement slip density is shown to be lower for the GLONASS system, than that for GPS. At mid-latitudes, the TEC slip mean density (N1 TECU/min) under quiet geomagnetic conditions practically does not depend on the Kp and AE index behavior, and does not exceed 12%. At high-latitudes, N1 TECU/min in winter is generally higher, than that in the summer, and may reach 50-60%. The N1 TECU/minvariation at highlatitudes correlates with the geomagnetic index behaviors; however, it depends on Kp and AE essentially differently. Under disturbed conditions, N1 TECU/min increases as AE grows more slowly, that it does under quiet conditions. On the contrary, N1 TECU/min growth as Kp increases under disturbed conditions occurs on a factor of 1,5 faster, than it does under quiet geomagnetic conditions. The N1TECU/min value dependences on the ionospheric disturbance index (Wtec) at mid- and high-latitudes are similar. An increase in the TEC slip density, N1TECU/min in wintertime occurs on a factor of 1,5 faster, than it does in summer. Simultaneously, at high-latitudes, the N1TECU/min growth with the Wtec increase occurs on a factor of 2-2,5 faster, than it does at the mid-latitudes.

Global distribution of GPS losses of phase lock and total electron content slips during the 2005 May 15 and the 2003 November 20 magnetic storms

Аннотация. На основе данных глобальной сети приемников GPS рассмотрены срывы сопровождения фазы навигационного сигнала GPS во время двух сильных магнитных бурь. Показано, что плотность сбоев на основной частоте L1 увеличивается до 0.25 %, на вспомогательной частоте L2 — до 3 %, в разы превышая фоновый уровень. Число сбоев измерения полного электронного содержания (ПЭС) во время супербури 20 ноября 2003 г. возросло в ~50 раз относительно фонового уровня. Обнаружено, что во время супербурь наибольшее число сбоев сопровождения фазы наблюдается в регионах низких и высоких широт. В то же время область наибольших сбоев измерения ПЭС соответствует границам аврорального овала.