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1.
During the type IV burst on 24 April, 1985 we observed at 234 MHz an untypical, strong, nearly six hours lasting continuum emission incorporating several groups of broadband pulsations, zebra patterns, fiber bursts, and a new fine structure phenomenon. The power spectra of the groups of broadband pulsations reveal no simple structure. There is only one common periodic component between 0.3 s and 0.4 s. Slowly drifting chains of narrowband fiber bursts are described as a new fine structure by spectrograms and simultaneously recorded single frequency intensity profiles. A qualitative model of this new fine structure is suggested. 相似文献
2.
The numerical algorithm of the Kalman optimum filtration generalized for the case of three-dimensional fields and a multicomponent vector of the ocean state, with level measurements discrete over space and time being available, is given. The results of model numerical experiments on the assimilation of data on the Black Sea level are given. An attempt to estimate the effect of the time interval of data input on the results of field reconstruction was made.Translated by Mikhail M. Trufanov. 相似文献
3.
A special fine structure (slowly drifting chains of narrowband fiber bursts), firstly observed during the solar type-IV radio burst on April 24, 1985, is interpreted as the radio signature of whistler waves periodically excited by a switch-on/switch-off process of a loss-cone instability in a localized wave packet of the fast magnetoacoustic mode. 相似文献
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The spectral fine structure of solar radio continua is thought to reveal wave-particle and wave-wave interactions in magnetic traps in the solar corona. We present observations of spectra, polarization, and spatial characteristics of combined emission/extinction features (zebra patterns) during a decimetric/metric type IV event on 5 June, 1990. Very high modulation depths are observed. The size and location of the sources during emission and extinction are determined for the first time. Two remarkable features are found: (1) The sources of emission stripes have finite size, up to nearly 2; during extinction stripes the brightness is reduced across the whole extent of the unperturbed continuum, which is slightly larger than 2. (2) During emission stripes the sources drift over distances up to several × 104 km, with apparent velocities up to 105 km s–1. The observed features are briefly discussed with respect to interpretations based on wave-particle interactions and on the scattering of electromagnetic waves. 相似文献
7.
We analyzed intermediately polarized (20–80%) fine structures (pulsations, sudden reductions, fiber bursts and zebras) that were recorded in type IV events. The mean polarization degree was practically the same for all the fine structures recorded in an interval lasting a few minutes and it was similar to the polarization of the continuum. A detailed analysis during the evolution of single structures reveals changes in polarization (in particular an undulation at flux density minima) even stronger than 20%. They were caused by a delay, up to 0.1 s, between the two circularly polarized components. The weaker polarimetric component was delayed in 2 sets and the stronger one in 1 set. In the event of April 24, 1985 different types of fine structures were sporadically detected in more than one hour long time interval. Short delays of the stronger or of the weaker component were sometimes observed.The events characterized by fine structures are generally totally polarized in the ordinary mode. We assume that this holds also for the phenomena studied here. The observed intermediate polarization therefore requires a depolarization due to propagation effects. We discuss the mode coupling and the reflection of the original radio signal that could also generate the delay of the weaker and the stronger component respectively. The possibility of polarization variation due to the change of the angle between the direction of the propagation and the magnetic field in a quasi-transversal region and in a low intensity magnetic field in a current sheet is also given.Presented at the CESRA-Workshop on Coronal Magnetic Energy Release at Caputh near Potsdam in May 1994. 相似文献
8.
M. V. Panchenko T. B. Zhuravleva V. S. Kozlov I. M. Nasrtdinov V. V. Pol’kin S. A. Terpugova D. G. Chernov 《Russian Meteorology and Hydrology》2016,41(2):104-111
The results of numerical simulation of downward solar radiation fluxes for background and smoke-contaminated atmospheric conditions are discussed. Vertical profiles of aerosol characteristics are obtained from the empirical model based on the data of aircraft sounding of profiles of angular scattering coefficients and content of absorbing particles in the lower troposphere. The background model was created using the results of measurements obtained under cloudless and mostly cloudless atmospheric conditions in 1999–2011. Optical parameters of smoke aerosol are determined from the data of aircraft measurements in the period of long-term wildfires in Siberia in the summer 2012. It is demonstrated that deficiency in diurnal values of total solar radiation at the surface level caused by the formation of the optically dense smoke layer as compared to background conditions, is more than 13 MJ/m2. 相似文献
9.
S. V. Chernov 《Astronomy Reports》2016,60(6):579-585
The full version of the magnetohydrodynamical (MHD) theory of accretion of a perfect fluid with an ultrahard equation of state, p = μ ~ ρ2 (where p is the pressure, μ the total energy density, and ρ the fluid density), onto a moving Schwarzschild black hole is considered. Exact and approximate analytical solutions have been found. It is shown that smooth continuous solutions exist only in the case when a single critical sound surface is formed. 相似文献
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