Analyzing solar, cosmic, and geophysical events in September 2017 using SHIСRA SB RAS complex observations

We report the results of monitoring of cosmic rays and geomagnetic field along 210 magnetic meridians in Yakutia in the first half of September 2017. The energy spectrum of solar cosmic rays during Ground Level Enhancement in September 10, 2017 is estimated as J=3027E–1.99exp(–E/729 MeV). We present the results of the forecast and complex analysis of the magnetic storm on September 7–9, 2017 with Dst=–124 nT. The forecast lead time is about one day. We examine how the storm affected the electric potential and VLF signal propagation from RSDN-20 radio navigation stations. Irregular Pi3–Pi1 pulsations occurred during the September 8, 2017 magnetic storm from 12 to 20 UT. The pulsations were accompanied by variations in electrotelluric potentials and geomagnetic fields with the correlation coefficient between them ρ(E, H)=0.5÷0.9. The effects of the magnetic storm manifested themselves as an increase in the attenuation and a decrease in the phase delay of VLF radio signals

Narrow-band emission with 0.5 to 3.5 Hz varying frequency in the background of the main phase of the 17 March 2013 magnetic storm

We present results of the analysis of an unusually long narrow-band emission in the Pc1 range with increasing carrier frequency. The event was observed against the background of the main phase of a strong magnetic storm caused by arrival of a high-speed solar wind stream with a shock wave in the stream head and a long interval of negative vertical component of the interplanetary magnetic field. Emission of approximately 9-hour duration had a local character, appearing only at three stations located in the range of geographical longitude λ=100–130 E and magnetic shells L=2.2–3.4. The signal carrier frequency grew in a stepped mode from 0.5 to 3.5 Hz. We propose an emission interpretation based on the standard model of the generation of ion cyclotron waves in the magnetosphere due to the resonant wave-particle interaction with ion fluxes of moderate energies. We suppose that a continuous shift of the generation region, located in the outer area of the plasmasphere, to smaller L-shell is able to explain both the phenomenon locality and the range of the frequency increase. A narrow emission frequency band is associated with the formation of nose-like structures in the energy spectrum of ion fluxes penetrating from the geomagnetic tail into the magnetosphere. We offer a possible scenario of the processes leading to the generation of the observed emission. The scenario contains specific values of the generation region position, plasma density, magnetic field, and resonant proton energies. We discuss morphological differences of the emissions considered from known types of geomagnetic pulsations, and reasons for the occurrence of this unusual event

Features of formation of small-scale wave disturbances during a sudden magnetospheric compression

Quasi-periodic changes of the geomagnetic field and plasma parameters in the range of Pc 5 pulsations, which occurred immediately after the interaction of interplanetary shock (IPS) with Earth’s magnetosphere in the event of April 24, 2009 at 00:53 UT are examined using ground and satellite observations. The pulsations were localized at latitudes 66–74° in the noon (11 MLT) and evening (20 MLT) sectors. The analysis of hodographs of the geomagnetic field changes both from satellite and ground observations has shown the presence of vortical disturbances. In this event, both the IPS front in the interplanetary medium and the compression wave front in the magnetosphere had a slope in the ZGSM=0 plane; the inclination angle was 14° in the interplanetary medium and 34° in the magnetosphere

АНАЛИЗ ЯВЛЕНИЙ КОСМИЧЕСКОЙ ПОГОДЫ В 2014 ГОДУ ПО НАБЛЮДЕНИЯМ В СЕВЕРО-ВОСТОЧНОМ РЕГИОНЕ РОССИИ

Рассмотрены геофизические эффекты солнечных событий 2014 г. по системе наблюдений северо-востока России. Выявлены эффекты возбуждения волн в атмосферном электричестве приземного слоя воздуха в результате внезапного начала магнитной бури. Накануне событий 4 ноября 2014 г. и 27 августа 2014 г. в ионосфере выделены положительные аномалии, которые возникали независимо от местного времени на фоне спокойного и слабовозмущенного геомагнитного поля

Monitoring and investigating space weather effects with meridional chain of instruments in Yakutia: a brief overview

The Yakutsk Meridional Chain (YMC) of IKFIA SB RAS, located along the 190° magnetic meridian, is equipped with geophysical and radiophysical instruments for monitoring space weather in northeast-ern Russia. YMC includes four basic stations in Yakutsk, Tixie, Zhigansk, and Maymaga, and six additional observation sites in Neryungri, Zyryanka, Kystatyam, Dzhardzhan, Chokurdakh, and Kotelny Island. It provides continuous monitoring of near-Earth space in order to obtain data on magnetic field variations, cosmic radio noise, VLF radiation, and ionospheric parameters in the complex upper atmosphere – ionosphere –magnetosphere system. In addition, long-term experimental research into space weather effects on human health is conducted at Tixie and Yakutsk. The report describes the meridional chain of instruments at subauroral and auroral latitudes and gives a brief overview of scientific results of monitoring and investigation into space weather effects in Yakutia. It also observes participation of IKFIA SB RAS in international projects (Intermagnet, MAGDAS, GIRO)

Simultaneous observations of the plasma density on the same field line by the CPMN ground magnetometers and the Cluster satellites

International audienceBy applying the cross-phase method and the amplitude-ratio method to magnetic field data obtained from two ground stations located close to each other, we can determine the frequency of the field line resonance (FLR), or the field line eigenfrequency, for the field line running through the midpoint of the two stations. From thus identified FLR frequency we can estimate the equatorial plasma mass density (p) by using the T05s magnetospheric field model [Tsyganenko, N.A., Sitnov, M.I. Modeling the dynamics of the inner magnetosphere during strong geomagnetic storms, J. Geophys. Res, 110, A03208, 2005] and the equation of Singer et al. [Singer, H.J., Southwood, D.J., Walker, R.J., Kivelson, M.G. Alfven wave resonances in a realistic magnetospheric magnetic field geometry, J. Geophys. Res. 86 (A6) 4589 4596, 1981].In this study we compare p estimated from magnetometer data at two stations in the CPMN (Circum-pan Pacific Magnetometer Network) chain, Tixie (TIK, geographic coordinates: 71.59 degrees N, 128.78 degrees E, L = 6.05) and Chokurdakh (CHD, geographic coordinates: 70.62 degrees N, 147.89 degrees E, L = 5.61), with the plasma electron number density (Ne) observed by the WHISPER (Waves of High frequency Sounder for Probing the Electron density by Relaxation) instrument onboard the Cluster satellites. For the interval of January 1, 2001 December 31, 2005, we have identified 19 events in which the Cluster spacecraft were located on the field line running through the midpoint of TIK and CHD when they observed FLR, and statistically compared the simultaneously observed 1) and Ne, although the number of events Lire limited (19). In 15 Out of the 19 events the ratio of p to Ne falls into a realistic range. it is also suggested that the contribution of heavy ions tends to increase when the magnetosphere is disturbed