Емельянов Н.В., Arlot J.E., Zhang X.L., Bradshaw J., De Cat P., Han X.L., Иванцов А., Jindra J., Майгурова Н., Manek J., Pauwels T., Помазан А., Vingerhoets P. «Астрометрические результаты наблюдений взаимных покрытий и затмений Галилеевых спутников Юпитера, выполненных в 2009 и 2014–2015 годах» Астрономический вестник. Исследования Солнечной системы, 53, № 6, с. 428-435 (2019)

Фотометрические наблюдения спутников во время их взаимных покрытий и затмений являются ценным источником астрометрических данных для изучения динамики естественных спутников-планет. Для того, чтобы наблюдать как можно больше явлений, организуются всемирные кампании фотометрических наблюдений. Все фотометрические результаты, полученные во время кампании наблюдений, помещаются в единую базу данных и через некоторое время подвергаются астрометрической обработке. После проведения кампании и публикации результатов некоторые наблюдатели обнаружили неиспользованные данные, которые представляются ценными. Мы собрали такие фотометрические наблюдения взаимных покрытий и затмений Галилеевых спутников Юпитера, которые поступили после проведения кампании, и обработали их, чтобы использовать эти ценные астрометрические данные. Для получения астрометрических данных из фотометрических наблюдений мы применяли наш оригинальный метод. Наблюдения проводились в восьми обсерваториях мира. В итоге, в данной работе представлены 32 новых относительных астрометрических положения Галилеевых спутников Юпитера, датированных 2009 годом, и 23 новых положения на даты 2014–2015 гг. Астрометрическая точность новых данных в сравнении с наиболее развитой теорией (О–С) составляет примерно 0.05''. Внутренняя точность по оценкам случайных ошибок фотометрии оказалась равной 0.02''. DOI: 10.1134/S0320930X1906001X

Beletskii A.B., Rakhmatulin R.A., Syrenova T.Ye., Vasilev R.V., Mikhalev A.V., Pashinin A.Yu., Shiokawa K., Nishitani N. «Preliminary results of simultaneous recording of auroral and geomagnetic pulsations at the ISTP SB RAS station Istok» Солнечно-земная физика, 5, № 2, с. 42-48 (2019)

The paper presents the results on first synchronous observations of variations in auroral luminosity and geomagnetic field, made with high temporal resolution at the ISTP SB RAS high-latitude station Istok (70°N, 88°E) in September–December 2018. Auroras were recorded with all-sky camera, pulsations in the auroras were recorded by a photometer in four spectral ranges with silicon photomultipliers. Continuous monitoring of geomagnetic pulsations was performed using a LEMI-30 three-component induction magnetometer. Both synchronous bursts of auroras and magnetic field pulsations, as well as disturbances of auroras, not accompanied by disturbances in the geomagnetic field, were observed. We note that the photometer clearly recorded short-period (∼20 min) variations in in auroral luminosity. At the same time, some instability of the photometer signal level occurred at sufficiently long time intervals. In the photometer data, there are powerful signal bursts, probably of a hardware nature. Nevertheless, the temporary distribution analysis of the registration moments (registration frequency) of signal bursts indicates the possible dependence of the burst registration frequency on the geomagnetic activity level.

Scafetta N., Milani F., Bianchini A. «Multiscale analysis of the instantaneous eccentricity oscillations of the planets of the solar system from 13.000 BC to 17.000 AD» Письма в Астрономический журнал: Астрономия и космическая физика, 45, № 11, с. 830 (2019)

The high-resolution Jet Propulsion Laboratory DE431 and DE432 planetary ephemeris are used to evaluate the instantaneous eccentricity functions of the orbits of the planets of the solar system from 13.000 BC to 17.000 AD at different time scales. Spectral analyses are performed to determine the frequencies and the amplitudes of the detected perturbations from 0.1-year to 10.000-year periods. Taken as contiguous pairs (Mercury–Venus, Earth–Mars, Jupiter–Saturn, and Uranus-Neptune), we found anti-phase patterns between contiguous planets at specific time scales (30.000 years): namely, the eccentricity of one planet increases while the other decreases. Venus and Earth instead appear in phase. However, on shorter time scales the phase coupling becomes more complex and irregular. Yet, Jupiter and Saturn present a π/2 phase coupling at the 1000-year scale. Periodogram analysis of the planetary eccentricity functions shows several fast fluctuations whose magnitudes indicate the strength of their mutual interactions where the Jovian planets significantly perturb the orbits of the inner planets. Besides, the wavelet power spectrum and wavelet squared coherence spectrum analyses are adopted to examine the relationships in time-frequency space between the eccentricity functions of each couple of terrestrial and Jovian planets. The analysis reveals the complexity and the evolution of the gravitational couplings perturbing each other planetary orbits. In some cases and for specific frequencies, this analysis technique also led to the discovery that the coherence phase can rotate clockwise or anticlockwise. The eccentricity function of the orbit of Jupiter presents large oscillations with periods of about 60 and 900–960 years, mostly due to the interaction with Saturn. These oscillations also correspond to oscillations found in several geophysical records. The eccentricity functions of Uranus and Neptune are characterized by a large 4.300-year oscillation. The eccentricity function of Pluto is characterized by a large nearly 20.000-year modulation. DOI: 10.1134/S0320010819110123

Lunyushkin S.B., Mishin V.V., Karavaev Yu.A., Penskikh Yu.V., Kapustin V.E. «Studying the dynamics of electric currents and polar caps in ionospheres of two hemispheres during the August 17, 2001 geomagnetic storm» Солнечно-земная физика, 5, № 2, с. 17-29 (2019)

The magnetogram inversion technique (MIT), developed at ISTP SB RAS more than forty years ago, has been used until recently only in the Northern Hemisphere. In recent years, MIT has been improved and extended to make instantaneous calculations of 2D distributions of electric fields, horizontal and field-aligned currents in two polar ionospheres. The calculations were carried out based on one-minute ground-based geomagnetic measurements from the worldwide network of stations in both hemispheres (SuperMAG). In this paper, this extended technique is used in the approximation of uniform ionospheric conductance and is applied for the first time to calculations of equivalent and field-aligned currents in two hemispheres through the example of the August 17, 2001 geomagnetic storm. We have obtained the main and essential result: the advanced MIT-ISTP can calculate large-scale distributions of ionospheric convection and FACs in the Northern (N) and Southern (S) polar ionospheres with a high degree of expected hemispheric similarity between these distributions. Using the said event as an example, we have established that the equivalent and field-aligned currents obtained with the advanced technique exhibit the expected dynamics of auroral electrojets and polar caps in two hemispheres. Hall current intensities in polar caps and auroral electrojets, calculated from the equivalent current function, change fairly synchronously in the N and S hemispheres throughout the magnetic storm. Both (westward and eastward) electrojets of the N hemisphere are markedly more intense than respective electrojets of the S hemisphere, and the Hall current in the north polar cap is almost twice as intense as that in the south one. This interhemispheric asymmetry is likely to be due to seasonal conductance variations, which is implicitly contained in the current function. From FAC distributions we determine auroral oval boundaries and calculate magnetic fluxes through the polar caps in the N and S hemispheres. These magnetic fluxes coincide with an accuracy of about 5% and change almost synchronously during the magnetic storm. In the N hemisphere, the magnetic flux in the dawn polar cap is more intense that that in the dusk one, and vice versa in the S hemisphere. These asymmetries (dawn-dusk and interhemispheric) in the polar caps are consistent with the theory of reconnection for IMF B_y>0 and with satellite images of auroral ovals; both of these asymmetries decrease during the substorm expansion phase.

Mityurich G.S., Lebedeva E.V., Aleksiejuk M., Serdyukov A.N. «Thermooptical excitation of sound by Bessel light beams in layered media with internal stress» Проблемы физики, математики и техники, № 3, с. 39-43 (2018)

Представлены результаты исследования фотоакустического преобразования различных мод БСП в гиротропных слоистых средах при пьезоэлектрическом методе регистрации результирующего сигнала. Показано, что амплитуда фотоакустического сигнала определяется теплофизическими характеристиками слоистых сред с внутренними напряжениями, коэффициентом поглощения и параметром кругового дихроизма гиротропных слоистых сред, поляризацией и энергетическими характеристиками БСП, частотой амплитудной модуляции, а также геометрией системы «пьезоэлектрический датчик–гиротропный слоистый образец».