Документы 31 - 40 из 49
31.

Количество страниц: 4 с.

The spatial-temporal distribution of westward electrojets in the northern hemisphere has been investigated using geomagnetic ground observation data for November 9-10, 2004 geomagnetic storm. It is shown that the location of the maximum westward electrojet depends on the IMF orientation. It is in the evening or morning sector when Bγ0. With the increase of positive IMF Bγ, the region of intensity maximum shifts to morning hours. Thus, the azimuthal IMF component not only controls the pattern of magnetospheric convection, but also affects the longitudinal location of the westward electrojet pattern during the magnetic storm.

Influence of IMF by on the location of western electrojets during the magnetic storm on Nov. 9-10, 2004 / R. N. Boroev, A. Du, S. I. Solovyev, W.-Y. Xu, G.-X. Chen, V. A. Velichko // Physics of auroral phenomena : proceedings of the 29th annual seminar, Apatity, 27 February–3 March 2006. – 2007. – P. 21-24.

32.

Количество страниц: 4 с.

Galactic cosmic ray (GCR) diffusion in interplanetary space depends in a certain way on the degree of regularity of the interplanetary magnetic field (IMF). The sector IMF structure is manifested in inhomogeneous GCR distribution in the heliosphere. In parallel with the usual sectors associated with solar activity, one should take into account the sectors, which are caused by the Jupiter activity. It is known that the Jupiter is a powerful regular source of high-energy electrons (0.2-40 MeV), the density of which, on the average, is many times higher than that of solar cosmic rays. The high-energy electrons are systematically registed with the 399-day period in the near-Earth space. According to estimations of the particle energy density their flux is sufficient to decrease the magnetic field in the Jovian sector and can due to corresponding large-scale inhomogeneity in the GKL distribution. Hereby, we present the evidences that the GCR diffusion is noticeably stronger in the sector where there are Jovian electrons. By data on periodic passage of those sectors near the Earth, we have treated neutron monitor data using the superposed epoch technique. The day of the Earth and Jupiter opposition is taken as a zero epoch. At large statistical data (9925 days) it is found that the GCR intensity in that period increases with an amplitude near 1%. The groud effect is manifested with the period of 399 days and its maximum time is in a certain way shifted relative to the planet opposite moment.

Skryabin, N. G. Influence of Jupiter on cosmic ray intensity variations / N. G. Skryabin, S. N. Samsonov, I. Ya. Plotnikov // Physics of auroral phenomena : proceedings of the 25th annual seminar, Apatity, 26 February – 1 March 2002. – 2002. – P. 137-139.

33.

Количество страниц: 4 с.

By using data treatment results of mid-latitude geomagnetic variations, the significant increase of the local current system intensity with the eastern direction current system, arising near the meridian of expected substorm center ~10-30 min before the break-up onset, has been found. A comparison of longitudinal sizes of two current system, forming the substorm disturbance before and after the onset of the substorm expansion phase, has been carried out. The longitudinal size of the current loop of the substorm growth phase is nearly twice as small as azimuth scale of the substorm current wedge, and the current strength is as week as 2.7-12 times.

Boroyev, R. N. Local increase of field-aligned current intensity before a substorm onset / R. N. Boroyev, V. A. Velichko, D. G. Baishev // Proceedings of the Fifth International Conference on Substorms : 16-20 May 2000 Congress Centre of the Arctic and Antarctic Research Institute, St. Petersburg, Russia. − Noordwijk, Netherlands : European Space Agency, 2000. − P. 279-282.

34.

Количество страниц: 1 с.

MAGDAS-9 magnetometers observations of strong earthquakes : [тезисы докладов] / Baishev D. G., Moiseev A.V., Bondar E. D., Kobyakova S. E., Yumoto K. // 10th International conference "Problems of geocosmos", St. Petersburg, Petrodvorets, October 6-10, 2014. – St. Petersburg : [s. n.], 2014. – P. 106.

35.

Количество страниц: 4 с.

Analysis of the global magnetosphere-ionosphere response to solar wind dynamic pressure variations under the negative IMF Bz has been performed. It is shown that an increase in the dynamic pressure leads to a double response of the ionospheric currents and aurora, i.e. simultaneously (within the accuracy of 1 min) and ~5-7 min afterward. Thereby, the eastward and westward convective electrojets are enhanced in the evening and morning sectors respectively, followed by the intensification of the westward current in the near midnight and evening sectors. The intensification of the electrojets is followed by extension of the diffuse precipitation zone and its high latitude boundary movement to the pole and to the east in the midnight-to-morning sector. In our case, no poleward or westward extension of aurora before midnight is observed. The disturbance triggered by a dynamic pressure increase may be considered as a convection disturbance associated with reconstruction of the DP2 current system.

Magnetosphere-ionosphere response to magnetosphere compression by the solar wind / S. I. Solovyev, A. V. Moiseyev, K. Yumoto, M. Engebretson // Physics of auroral phenomena : proceedings of the 26th annual seminar, 25 - 28 February 2003. – 2003. – P. 41-44.

36.

Количество страниц: 2 с.

Magnetospheric-ionospheric response to variations in the solar wind dynamic pressure during positive IMF Bz and a sharp change of IMF By direction : [тезисы докладов] / S. I. Solovyev, A. V. Moiseyev, K. Yumoto, M. Engebretson, A. Du // Physics of auroral phenomena : 29th annual seminar, 27 February – 3 March 2006 : abstracts. – 2006. – P. 36.

37.

Количество страниц: 4 с.

Large-amplitude morning Pc5 magnetic pulsations during the main phase of intense magnetic storm were registered at magnetic stations of 190-200° magnetic meridians on January 21-22, 2005. Magnetic pulsations in the Pc5 frequency range observed at the GOES 10, 12 satellites in the noon and evening sectors exhibited a high degree of magnetic compessibility. A Los Alamos particle detector on board geostationary satellite observed the occurrence of energetic particle flux oscillations in the Pc5 band. The Pc5 pulsations were followed with the VLF-emission and riometer absorption modulation with the same period. The regions of maximal amplitude of Pc5 geomagnetic pulsations and deep modulation of riometer absorptions shifted to high latitudes in the same way. Significant and long-lasting compression of magnetosphere led, probably, to moderate pitch-angle diffusion of particle into the loss cone even at the middle latitudes. Analysis of coordinated data allowed us to suggest that a modulation effects of precipitating particles are caused by a compressional waves.

Manifestation of Magnetosphere Fluctuations during the Large Magnetic Storm of January 21-22, 2005 / D. G. Baishev, E. S. Barkova, V. A. Mullayarov, S. N. Samsonov, S. I. Solovyev, K. Yumoto // Solar Extreme Events Fundamental Science and Applied Aspects Nor-Amberd, Armenia 26-30 September 2005 : proceedings of the Second International Symposium / edited by A. Chilingarian and G. Karapetyan. − Erevan : Cosmic Ray Division, Alikhanyan Physics Institute, 2006. − P. 96-99.

38.

Количество страниц: 4 с.

The results of the hydroxyl and oxygen molecules rotational temperature measurements during two observational seasons 1999-2001 at Maymaga station (φ=63°N;λ=129.50°E) are presented. The rotational temperatures of OH(6,2) and O2 (0,1) bands have been measured with the infrared spectrograph equipped by the cooled CCD registration system. It is shown that the amplitude of seasonal change of hydroxyl rotational temperature is greater than the molecular oxygen variation. OH temperatures have been systematically higher the O2 ones during winter. An abrupt decrease of the O2 intensity connected with the springtime transition of the atmospheric circulation is found in both time series. For the first time a change of the temperature vertical gradient sign caused by mesopause height displacemet to a higher (winter) level was shown in the data of August-September 2001.

Gavrilyeva, G. A. Measurements of the mesosphere temperature by two molecular emissions in Yakutsk (62°N, 129,5°E) / G. A. Gavrilyeva // Physics of auroral phenomena : proceedings of the 26th annual seminar, 25 - 28 February 2003. – 2003. – P. 198-201.

39.

Количество страниц: 3 с.

Statistical analysis of internal gravity wave parameters registered by variations of the hydroxyl molecule emission is presented. The wave structures are detected with an all sky infrared camera at the optical station of Maimaga (φ=63° N; λ=129.50°E geographic). The data obtained for the period of 1998 to 2002 show that the small-scale internal gravity waves propagate predominantly westward. The observed wavelengths vary from 15.4 to 100 km. (the average value is ~40 km), the horizontal phase speeds are between 19 and 166 m s-¹ (the average value is ~63 m s-¹) and the estimated periods are 9-90 min (the average value is ~17 min). The wavelengths and phase speeds at high latitudes is probably due to the large intensities of the filtering winds compared to those in the middle atmosphere. The short waves (wavelengths shorter than 17.5 km) propagate in the same direction as the long ones.

Ammosov, P. P. Observations of short-term waves with an all sky camera in the infrared oh brightness over Yakutsk / P. P. Ammosov, G. A. Gavrilyeva // Physics of auroral phenomena : proceedings of the 26th annual seminar, 25 -28 February 2003. – 2003. – P. 179-181.

40.

Количество страниц: 4 с.

The Dst-index obtained by hourly average values of the magnetic field at four stations located in various longitudinal sectors at latitudes Φ′≈20-30° is the index of magnetic field depression at low latitudes during the magnetic storm periods. Recently for the characteristics of magnetic field depression the SYM-H index has been used. It is obtained from 1 min data of the magnetic field at ~10 stations, located mainly at latitudes Φ′≈40-50° [1]. It is considered in [2-4] that the SYM-H index is an analog of Dst but with a better temporal resolution. As shown in [5], during super magnetic storms with Dst variation ≥ 400 nT, the SYM-H variations can considerably differ from Dst behavior and thus the SYM-H index is not always an analog of Dst. In this paper the relation between the Dst and SYM-H variations for magnetic storms of different intensity, with Dst varying from ~ -50 nT to -450 nT is investigated.

Solovyev, S. I. On the relation between the SYM-H and Dst- indices during the development of magnetic storm / S. I. Solovyev, R. N. Boroyev, A. V. Moiseyev // Physics of auroral phenomena : proceedings of the 28 th annual seminar, 1-4 March 2005. – 2005. – P. 48-51.