Solar wind and interplanetary magnetic field effects in the magnetosphere-ionosphere system

The research presented in this thesis investigates several effects in the magnetosphere-ionosphere system related to specific solar wind and interplanetary magnetic field drivers. For the southward Interplanetary Magnetic Field (IMF) when the coupling between the solar wind and the magnetosphere is efficient, the energy accumulation in the magnetotail is often interrupted by a spontaneous energy release into various parts of the magnetosphere-ionosphere system through a substorm process. When the IMF turns northward, the dayside reconnection is inefficient and the lobe reconnection becomes important. Onset of sunward flows in the dayside portion of the polar cap ionosphere is one effect related to this process. Another phenomenon under northward IMF is the occurrence of auroral arcs at very high latitudes. This thesis is focused of these three phenomena: substorms, dayside sunward plasma flows and the onset of polar cap arcs. First, the relationship between the substorm occurrence and the solar wind driving is statistically investigated. Four independent lists of substorm events are considered. The events in these lists are inferred from jumps in the SuperMAG AL index for 1979–2015, from electron injections into geosynchronous orbit for 1989–2007, from positive bay events in 1982–2012, and from ground-based magnetometer data with the SOPHIE algorithm for 1981–2015. Additionally, a well-known list of substorms identified from IMAGE and Polar satellite imagery is considered. The different lists are investigated and the two lists with the most robust substorm onsets are chosen for further study. Substorm occurrence rates and substorm recurrence-time distributions are examined as functions of the phase of the solar cycle, the season of the year, the Russell-McPherron favorability, the type of solar wind plasma at Earth, the geomagnetic-activity level, and as functions of various solar and solar wind properties. Three populations of substorm occurrences are seen: (1) quasiperiodically occurring substorms with recurrence times of 24 hr, (2) randomly occurring substorms with recurrence times of about 6–15 hr, and (3) long intervals where no substorms occur. A working model is suggested where (1) the period of periodic substorms is set by the magnetosphere with variations in the actual recurrence times caused by the need for a solar wind driving interval to occur, (2) the mesoscale structure of the solar wind magnetic field triggers the occurrence of the random substorms, and (3) the large-scale structure of the solar wind plasma is responsible for the long intervals where no substorms occur. Statistically, the recurrence time of periodically occurring substorms is slightly shorter when the ram pressure of the solar wind is high, when the magnetic field strength of the solar wind is strong, when the Mach number of the solar wind is low, and when the polar-cap potential saturation parameter is high. Second, SuperDARN radar data are used to investigate polar cap ionospheric flows under strongly dominant northward IMF. By considering line-of-sight velocities from SuperDARN radars looking in the meridional direction, it is shown that the near-noon flow is predominantly sunward in summer. The sunward velocity increases with intensification of the flow driver (the reverse convection electric field); the effect is stronger in summer and in the Southern hemisphere. Statistical patterns of the sunward flows along the noon-midnight meridian clearly indicate seasonal differences in the intensity and flow direction. Simultaneous SuperDARN convection maps in both hemispheres, averaged over periods of approximately two hours, show that sunward flows are faster in the summer hemisphere. In addition to this, while the sunward flows are aligned with the midnight-noon line in a winter hemisphere, they are oriented toward earlier magnetic local hours in a summer hemisphere. Finally, data from the SuperDARN radars and DMSP and Swarm satellite are used to investigate plasma flows around polar cap arcs. Two cases of arcs, that are just detached from the auroral oval, are considered — one in the morning sector and one in the evening sector. It is shown that polar cap arcs introduce mesoscale structuring of the global convection pattern in the polar cap, and clear flow shears occur. The shears are interpreted as a superposition of the background plasma flow and relatively narrow channels of plasma flow intrinsically related to the polar cap arcs. PolarDARN radar observations at close ranges consistently indicate sunward flows collocating with the arcs. This result is additionally supported by DMSP satellite observations. According to the SuperDARN data, the detached arcs are preceded in time by the flow of the plasma from the auroral oval to the polar cap. It is hypothesised that such inflows are indicators that the formation of polar cap arcs is related to instability processes in the plasma sheet

ТИПОЛОГІЯ І СТРУКТУРА СЕЛЯНСЬКОЇ РОДИНИ СТАРОДУБСЬКОГО ПОЛКУ В ДРУГІЙ ПОЛОВИНІ XVIII ст. (НА ПРИКЛАДІ СІЛ КОМАН ТА КУДЛАЇВКА НОВГОРОДСЬКОЇ СОТНІ) ((Typology and structure of peasant family Starodybskiy regiment in the second half of the 18th century. (on the sample villages Koman and Kudlaevka Novhorodskaya sotnya))

У статті аналізуються показники загальної і середньої населеності, поколінний склад, типологія та структура селянських домогосподарств сіл Коман і Кудлаївка Стародубського полку у другій половині XVIII ст. (In this article author examines one of poorly explored problems of native history – studying Ukrainian society in period of early modern time.

Романтично-сентиментальні засади повісті «Чебрець-зілля» Наталі Романович-Ткаченко

У статті розглянуто стильові особливості повісті «Чебрець-зілля» Наталі Романович-Ткаченко. З’ясовано місце романтизму й сентименталізму в художньому світі повісті. Окреслено проблемно-тематичні виміри твору. Виявлено особливості характеротворення. (The article considers the stylish features of the story «Chabrets-zillya» by Natalia Romanovich-Tkachenko. The place of romanticism and sentimentalizm in the artistic world of story is found out. The problem-thematic parameters of the work are outlined. The features of character creation are exposed.

Дослідження напружено-деформованого стану циліндра з мікроструктурними перетвореннями за умов імпульсного навантаження

Axisymmetric dynamic problem of thermomechanical loading of a steel cylinder is considered. Volume strain caused by the microstructural transformations of the martensitic type under cooling solids as well as into consideration and dependence inelastic characteristics of material for multiphase state are taken. The thermomechanical nonlinear behavior of an isotropic material is described by unified flow model generalized for the case of multiphase material state. The problem is solved numerically by the implicit step-by-step time integration method, by the iterative method and by the finite element method. The investigation of the stress-strain state of an inelastic material with regard for the dependence of parameters of the flow model on the phase composition of a material is carried out by using of numerical simulation. We established that microstructural transformations significantly reduce residual inelastic strain and promote the appearance of compressive stresses. The results obtained in the work can be used in calculations of parameters of surface hardening technologies. Pages of the article in the issue: 176 - 179 Language of the article: UkrainianРозглядається осесиметрична задача про імпульсне термомеханічне навантаження сталевого циліндра. Враховуються об’ємні деформації, які супроводжують мікроструктурні перетворення мартенситного типу при охолодженні тіл, а також залежність непружних характеристик матеріалу від фазового складу. Термомеханічна поведінка ізотропного матеріалу описується моделлю течії Боднера-Партома. Задача розв’язується чисельно методом покрокового неявного інтегрування за часом, ітераційним методом та методом скінченних елементів. За допомогою чисельного моделювання проводиться дослідження напружено-деформованого стану за умов врахування залежності параметрів моделі від мікроструктури матеріалу. Встановлено, що мікроструктурні перетворення суттєво зменшують залишкові деформації та сприяють появі стискальних напружень. Отримані результати можуть бути використані в інженерних розрахунках на міцність елементів конструкцій, а також параметрів технологій поверхневого зміцнення

Indexing the etymological lexicographic systems

Indexing the etymological lexicographic systems The main problems and directions for the development of the etymological lexicographic systems in the digital environment are studied. The formal conceptual model of the lexicographic system for fundamental academic Etymological Dictionary of the Ukrainian Language (EDUL) is developed. The lexicographic structure of the EDUL individual elements are developed and described. The EDUL metalanguage was studied and described. The formal model and technology of the EDUL parsing are worked out. That made it possible to convert automatically the EDUL text into the lexicographic database, which corresponds to the conceptual model of the lexicographic system. The conceptual foundations of instrumental tool to form the etymological dictionaries are developed to create the Virtual Lexicographic Laboratory «Etymological Dictionary of the Ukrainian Language», which was implemented with a modern approach to the real lexicographic array of the EDUL. That allowed to form the database of the EDUL multilingual index (about 250 languages) in the automatic mode. This index is a basis of the seventh (final) volume of the EDUL. The possibility of applying the developed models to other etymological dictionaries are studied. The conceptual foundations for integration of the etymological lexicographic systems are discussed