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Vol 63, No 3 (2023)

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Articles

Large-Scale Disturbances of the Solar Wind According to Spacecraft Radio Transmission Data from the Mars Express and Local Measurements on the Wind Spacecraft

Efimov A.I., Smirnov V.M., Chashei I.V., Nabatov A.S.

Abstract

The results of experiments on radio sounding of near the Sun plasma by the signals of the Mars
Express Mars satellite are presented. In the region of heliocentric distances of the proximate point of the line
of sight of 8–13 solar radii, frequency fluctuations of transmission radio signals were measured. During the
experiments sharp increases in the variance of frequency fluctuations were recorded on both the eastern and
western limbs. In measurements near the Earth’s orbit on the Wind spacecraft in adjacent periods with a delay
of 5–17 days, increases in the proton concentration and magnetic field strength were recorded at 7–15 times the
background values. A comparison between the data related to the inner and near-Earth solar wind indicates that
the observed disturbances are associated with the same region of the solar corona rotating with the Sun

Geomagnetizm i aèronomiâ. 2023;63(3):275-283
pages 275-283 views

Influence of the Gleissberg Cycle on Variations of the 11-Year Cycle of Solar Activity in 1700–2021

Ptitsyna N.G., Demina I.M.

Abstract

The wavelet analysis was used to study the spectral composition of the sunspot numbers SN during
1700–2021. In addition to the dominant 11-year component, two powerful components of the Gleissberg
cycle can be traced in the spectrum: before 1880, a branch with a period of ~60 years; from 1850 a branch of
~115 years is found. It is found that the series of lengths and amplitudes of the solar cycle as a whole are
inversely related (correlation coefficient k = –0.5–0.63). The interval between the series at which the maximum
anticorrelation is reached depends on time. In the 18th and early 19th centuries, the lag was equal to
one cycle, in the 19th century it was two cycles, and from 1950 to our time the lag decreased to 2 years. Quasiperiodic
structures, which are typical for long periods of low solar activity, have been identified. Such a spectral
feature in ~1800 (Dalton minimum) was caused by the influence of the 60-year branch, while the one
that has been forming since the beginning of the 21st century is due to the weaker influence of the circa-centenary
branch. Therefore, it should be expected that the next solar cycles will be higher and shorter than
during the period of the Dalton minimum. It has been shown that solar cycle length variations for the last
321 years can be described within the framework of the model, which is an 11-year oscillation that is subject
to frequency modulation by the branches of the Gleisberg cycle (60 and 115 years) with time-varying influences
of the modulator

Geomagnetizm i aèronomiâ. 2023;63(3):284-297
pages 284-297 views

Ветви резонансного ультранизкочастотного поглощения в магнитосфере Земли

Бадин В.

Abstract

Анализируются доплеровские наблюдения авроральной электроструи норвежским радаром STARE в течение одного солнечного оборота, предшествовавшего сильной магнитной буре. При этом наименьшая частота резонансного ультранизкочастотного поглощения определяется как частота ступенчатого падения спектральной плотности мощности наблюдаемого сигнала. В свою очередь, ч-астота ступенчатого падения спектральной плотности мощности определяется посредством решения минимальной вариационной задачи, которая наилучшим образом (метод наименьших квадратов) вписывает ступенчатую модель средней спектральной мощности в профиль спектральной плотности мощности реальных наблюдений. Последовательное сжатие спектрального окна, в котором решается вариационная задача, позволяет построить диаграммы решений минимальной задачи на плоскости частота – мощность резонансного поглощения. С помощью таких диаграмм выделены высокочастотная и низкочастотная ветви резонансного ультранизкочастотного поглощения. Обнаружено, что в слабовозмущенных условиях изменчивость резонансного ультранизкочастотного поглощения обусловлена, в первую очередь, вариациями мощности поглощения в обеих ветвях.

Geomagnetizm i aèronomiâ. 2023;63(3):298-305
pages 298-305 views

Selection of the Solar-Diurnal Anisotropy of Cosmic Rays by Local and Global Methods

Belov A.V., Shlyk N.S., Abunin M.A., Abunin A.A., Oleneva V.A., Yanke V.G., Melkumyan A.A.

Abstract

According to the data of Moscow neutron monitor, using harmonic analysis, the characteristics of
the solar-diurnal anisotropy of cosmic rays on quiet days have been obtained for a long period from 1965 to
2020. It has been established that the average diurnal variation of cosmic rays at the Moscow neutron monitor
is almost completely described by two harmonics of the solar-diurnal anisotropy and does not contain signs
of other influences. A comparison with the average daily characteristics of the equatorial component of cosmic
rays vector anisotropy, obtained from the data of the worldwide neutron monitor network using the global
survey method showed a good agreement between the results of the two methods. From a comparison of local
and global results, estimates were obtained for the coupling coefficients of the first harmonic of the cosmic
ray anisotropy for the Moscow neutron monitor, and a new experimental method for calculating the coupling
coefficients of individual detectors was proposed. The limitations of the local method, as well as the possibility
of continuing and expanding this study, have been discussed and justified

Geomagnetizm i aèronomiâ. 2023;63(3):306-320
pages 306-320 views

Prediction of Isolated Substorms by a Package of Parallel Neural Networks

Barkhatov N.A., Revunov S.E., Barkhatova O.M., Revunova E.A., Vorobjev V.G.

Abstract

A neural network forecast of substorms caused by the impact of solar wind plasma flows on the
Earth’s magnetosphere has been performed. For this, recurrent neural network models were created based on
physical cause-and-effect relationships of the dynamics of high-latitude geomagnetic activity (according to
the AL index) with the parameters of the interplanetary magnetic field (IMF) and solar wind plasma (SWP).
Two parameters are used as input sequences: the bz-component of the IMF and the integral parameter
Σ[NV2], taking into account the prehistory of the process of pumping the kinetic energy of the solar wind into
the magnetosphere, where N and V are the plasma density and solar wind velocity, respectively. The forecast
of the AL index according to SWP and IMF for 10 min, etc. with 10 min discreteness individually by an individual
artificial neural network (ANN) for each point corresponding to the dynamics of the AL index was
completed. This means that the prediction of a continuous series of values AL index is achieved by a parallel
running of the ANN package. The number of ANNs in the package is determined by the duty cycle of the
required predictive series of the AL index, while taking 90 min of the history of input parameters in each of
the networks into account provides a prediction of the values AL index with an accuracy of ~80%

Geomagnetizm i aèronomiâ. 2023;63(3):321-326
pages 321-326 views

Features of Polar Substorms: An Analysis of Individual Events

Kleimenova N.G., Gromova L.I., Despirak I.V., Malysheva L.M., Gromov S.V., Lyubchich A.A.

Abstract

Polar substorms include substorms observed at geomagnetic latitudes above 70° MLAT in the
absence of simultaneous negative magnetic bays at lower latitudes, that is, substorms on the compressed contracted
auroral oval. The general morphological features of polar substorms are considered based on the
example of individual events registered on Svalbard arch. It is shown that polar substorms, like “classical”
substorms, are characterized by the formation of a substorm current wedge and a steplike movement to the
pole after the onset of a substorm, generation of Pi2 geomagnetic pulsations, and an increase of the PC-index
of the polar cap before the onset of the substorm. At the same time, there are certain differences between polar
substorms and “classical” substorms; namely, they start on more distant L-shells, develop in the region of a
contracted auroral oval, occur at earlier pre-midnight hours, and generate only at low solar wind speeds and
weakly disturbed geomagnetic conditions. It has been suggested that polar substorms may be a specific type
of “classical” substorms that develop in the evening sector under magnetically quiet or weakly disturbed conditions
when the auroral oval is concracted. The source of polar substorms may also be a local intensification
of previously existing substorms in the post-midnight sector

Geomagnetizm i aèronomiâ. 2023;63(3):327-339
pages 327-339 views

Disturbances in the Magnetosphere and Ionosphere during Spotless Sun

Gulyaeva T.L.

Abstract

Analysis of geomagnetic and ionospheric activity is performed for 541 disturbed days during spotless
Sun (Kp > 3.0) from 1995 to 2021. Variations of the global ionospheric indices WU (positive disturbances
of total electron content), WL (negative disturbances), their range WE and the planetary index Wp are analyzed.
The source W-index characterizes a measure of deviation of the instant total electron content from the
quiet median varying from −4 to +4 with a step 1, and the global indices WU, WL, WE, Wp are derived from
the global maps GIM-TEC of Jet Propulsion Laboratory, JPL. Investigation of the seasonal dependence has
revealed two levels of the ionosphere disturbances: the low disturbance of the ionosphere during 1996‒1998
and 2018‒2021 and the high disturbance during 2004‒2010 and 2016‒2017. The seasonal ionosphere variations
are different for two sets of the data. The seasonal variations of the solar wind velocity Vsw near the Earth
orbit are first identified for the 1st data set displaying the peaks at the equinoxes similar to variations of the
Kp-index. The 2nd set of the high disturbance of the ionosphere refers to the epoch of transition from the high
solar activity SA to low SA characterized by the total restructuring of the physical conditions on the Sun

Geomagnetizm i aèronomiâ. 2023;63(3):340-348
pages 340-348 views

Effectiveness of the Relative -Barbier Parameter in the Search for Ionospheric Precursors of Earthquakes

Pulinets S.A., Khegai V.V., Legen’ka A.D., Korsunova L.P.

Abstract

A study of temporal variations of the complex relative δ-Barbier parameter (δBarbier) was carried out
to evaluate its effectiveness in the search for seismo-ionospheric precursors. For this purpose, its behavior
(according to 15-min measurements of ionospheric parameters) was considered before two strong earthquakes
for which seismo-ionospheric precursors had already been detected. The first earthquake (with magnitude
M = 6.3) occurred on April 6, 2009 (L’Aquila, Italy) at an epicentral distance of ~93 km from the Rome
ground-based vertical ionospheric sounding station, and the second earthquake (with magnitude M = 7.2)
occurred on January 30, 2016, while its epicenter was ~117 km from the ground-based vertical ionospheric
sounding station located on the territory of the Paratunka Kamchatka complex geophysical observatory. In
both cases, specific features were identified in the behavior of the δBarbier parameter that coincided in time
with the previously detected ionospheric precursors of these earthquakes. This allows us to conclude that the
effectiveness of using the δBarbier parameter in the search for seismo-ionospheric precursors has been successfully
verified

Geomagnetizm i aèronomiâ. 2023;63(3):349-357
pages 349-357 views

Coastal Effect in the Horizontal Components of the Electric Field

Ismagilov V.S., Kopytenko Y.A., Petrishchev M.S., Sergushin P.A., Petlenko A.V.

Abstract

The results of experimental studies of electric field disturbances generated by sources of an ionospheric
origin in the coastal zones of the White and Barents seas are presented. The data recording was performed
by geophysical stations GI-MTS-1. The horizontal electric field was recorded by telluric lines ~50 m
long. The Ex component was set orthogonally to the coastline in the direction from the shore, and the Еy
component was directed along the coastline. In the coastal strip of the sea–land contact, a zone of anomalous
increase in the amplitude of ULF variations (F < 1 Hz) of the Ex component adjacent to the water’s edge was
revealed. An additional narrow zone of anomalous amplification of the ULF variations of the electric field is
observed at a distance of ~30 m from the water’s edge. The coastal effect reaches its maximum near the
water’s edge in the coastal zone and decreases with distance from the seashore

Geomagnetizm i aèronomiâ. 2023;63(3):358-365
pages 358-365 views

Refined Spatio-Temporal Model of Accelerations of the Main Geomagnetic Field on the Earth’s Surface and Geomagnetic Jerks

Simonyan A.O., Ohanyan M.V.

Abstract

Refined spatial spherical harmonic models of the piecewise constant field of secular geomagnetic
accelerations have been constructed based on the concept of geomagnetic jerks. The data of the 189 magnetic
observatories operating during the extended period of investigations have been analyzed, assuming that jerks
are manifestation of sharp changes in regimes of quasi-stationary magnetohydrodynamic process of generation
of geomagnetic secular variations in the high-frequency spectrum range. Qualitative and quantitative
analyses have been carried out, showing the persistency of models of the current generation, and their consistency
with the acceleration field values obtained from direct observatory observations data. The epochs of
jerks that occurred in the extended time period were refined and it was found that on the global scale they
have quasi-decadal repeatability, through which it is possible to estimate the time characteristics of regimes
of the stationary evolution of the magnetic field of the Earth’s core. An analysis of the results of spherical harmonic
modeling using the maps of the global field of accelerations showed that the origins of all identified
jerks are of an intraterrestrial character, which also provide the specific features of their morphological structure,
as well as the degree of their distribution on the Earth’s surface

Geomagnetizm i aèronomiâ. 2023;63(3):366-390
pages 366-390 views

Thermal Regime of the Lithosphere under the Taimyr Peninsula According to Geomagnetic Data

Filippova A.I., Filippov S.V.

Abstract

This article presents the results of a study of the thermal regime of the lithosphere under the Taimyr
Peninsula and adjacent territories (70°–80° N, 80°–115° E) based on geomagnetic data. Spectral analysis of
the lithospheric geomagnetic field given by the EMAG2v3 model was performed using the centroid method.
The calculations we performed showed that the minimum depths of the top boundary of lithospheric magnetic
sources (<2.5 km) are typical for the entire Taimyr fold belt and the considered part of the Siberian Platform,
and the maximum (>6 km) for the North Kara Basin. The position of the top boundary of the magnetically
active layer of the lithosphere above the bottom of the sedimentary layer under the Yenisei-Khatanga
and Khatanga-Lena basins can be associated with the widespread intrusion of basalt traps into the sedimentary
layer. The minimum depths of the bottom boundary of lithospheric magnetic sources (<36 km) are confined
to the Eurasian Basin and neighboring territories of the Laptev Sea shelf and the islands of the Severnaya
Zemlya archipelago, which indicates the greatest heating of the lithosphere under them within the
region under consideration. The depth of the bottom boundary reaches maximum values (≥48 km) under the
Yenisei-Khatanga and North Kara basins and the Siberian Platform, indicating the existence of the cold and,
accordingly, thick lithosphere here, which is confirmed by other independent geophysical data

Geomagnetizm i aèronomiâ. 2023;63(3):391-402
pages 391-402 views

ДИСКУССИИ

Estimation of the Average Values of the Wolf Numbers of Cycles of the Dalton Minimum Based on the Characteristics of Reliable Cycles of a Series

Shibaev I.G.

Abstract

The source material for the number of Wolf numbers is both archival records of disparate observations
and regular observatory observations. Many researchers rely on a series of Wolf numbers, including
restored data of archival records, although the properties and characteristics of the restored and reliable parts
of the series differ significantly. The parameters of the restored part itself are also contradictory. Naturally,
matching the properties of the reconstructed and reliable series will smooth the contradictions and expand
the array of more reliable data. Taking the relationship between the characteristics of significant cycles into
account, options for group correction of the average values of cycles I–IX are presented. Since local data
residuals play a lesser role when comparing extended fragments, by relying on the integral estimates of these
fragments (without detailing the conditions for their formation) we obtained more weighted interval estimates.
The parameters of intervals (groups of cycles) of a reliable series serve as the basis for correction.

Geomagnetizm i aèronomiâ. 2023;63(3):403-408
pages 403-408 views