Currents of quasi-trapped particles and their interaction with the geomagnetic field /symmetrical approximation/

Currents of quasitrapped particles and their interaction with geomagnetic fiel

Effective area for the northern polar cap magnetic activity index

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94783/1/grl12045.pd

Invariability of relationship between the polar cap magnetic activity and geoeffective interplanetary electric field

The PC (polar cap) index characterizing the solar wind energy input into the magnetosphere is calculated with use of parameters α, β, and &phi;, determining the relationship between the interplanetary electric field (<i>E</i>_KL) and the value of magnetic activity &delta;<i>F</i> in the polar caps. These parameters were noted as valid for large and small <i>E</i>_KL values, and as a result the suggestion was made (Troshichev et al., 2006) that the parameters should remain invariant irrespective of solar activity. To verify this suggestion, the independent sets of calibration parameters α, β, and &phi; were derived separately for the solar maximum (1998–2001) and solar minimum (1997, 2007–2009) epochs, with a proper choice of a quiet daily variation (QDC) as a level of reference for the polar cap magnetic activity value. The results presented in this paper demonstrate that parameters α, β, and &phi;, derived under conditions of solar maximum and solar minimum, are indeed in general conformity and provide consistent (within 10 % uncertainty) estimations of the PC index. It means that relationship between the geoeffective solar wind variations and the polar cap magnetic activity responding to these variations remains invariant irrespective of solar activity. The conclusion is made that parameters α, β, and &phi; derived in AARI#3 version for complete cycle of solar activity (1995–2005) can be regarded as forever valid

PC индекс как показатель энергии солнечного ветра, поступающей в магнитосферу (итоги)

The paper includes a short review of advantages of the PC index which is a characteristic of the magnetic activity in the polar caps in the northern (PCN) and southern (PCS) hemispheres. It is demonstrated that the PC index properly responds to variations of the geoeffective interplanetary electric field E coupling with the magnetosphere, on the one side, and predetermined the development of magnetospheric disturbances (magnetic storms and substorms), on the other side. These experimental results formed the physical backgrounds for concept that the ground-based PC index characterizes the solar wind energy input into the magnetosphere. It is shown that problem of random discordances in behavior and value of the PCN and PCS indices during the summer/winter seasons is easily solved by choosing the PC index in the winter polar cap (PCwinter) as the best characteristic of the polar cap magnetic activity. At present the PC index is successfully applied to validate the utility of SW data presented at OMNI website (i.e. to verify whether or not the solar wind, measured in the Lagrange point, encountered the magnetosphere in reality). A special procedure agreed by the Arctic and Antarctic Research Institute (responsible for production of PCS index) and DTU Space (responsible for production of PCN index) ensures the calculation of the 1-min PC indices in quasi-real time based on data of magnetic observations at the polar cap stations Vostok (Antarctic) and Qaanaaq (Greenland).Дается краткий обзор достижений, полученных при использовании индексов магнитной активности в северной (PCN) и южной (PCS) полярных шапках. Показано, что PC индекс четко отвечает на вариации геоэффективного межпланетного электрического поля E, взаимодействующего с магнитосферой, с одной стороны, и является предвестником магнитосферных возмущений (магнитных бурь и суббурь), с другой стороны. Эти экспериментальные факты послужили основой представления о PC индексе как характеристике энергии солнечного ветра, поступающей в магнитосферу. Показано, что проблема случайных расхождений в поведении и величине PCN и PCS индексов в сезоны зима/лето решается выбором PC индекса в зимней шапке (PCwinter) как наиболее адекватной характеристики магнитной активности. В настоящее время PC индекс успешно применяется при оценке пригодности данных сайта OMNI о параметрах солнечного ветра (т.е. для проверки реальности контакта с магнитосферой солнечного ветра, измеренного в точке либрации). Специальная процедура, согласованная Арктическим и антарктическим НИИ (который ответственен за производство PCS индекса) и Датским техническим университетом (который ответственен за производство PCN индекса), обеспечивает расчет в реальном времени 1-мин PC индекса по данным магнитных наблюдений на полярных станциях Восток (Антарктика) и Туле (Гренландия)

Polar cap index (PC) as a proxy for ionospheric electric field in the near‐pole region

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95640/1/grl13514.pd

Влияние космической погоды на земную атмосферу

The review generalizes experimental data on the relationships between the solar activity agents (space weather) and atmosphere constituents. It is shown that high-energy solar protons (SPE) make a powerful impact on photo-chemical processes in the polar areas and, correspondingly, on atmospheric circulation and planetary cloudiness. Variations of the solar UV irradiance modulate the descent rate of the zonal wind in the equatorial stratosphere in the course of quasi-biennial oscillation (QBO), and thus control the total duration (period) of the QBO cycle and, correspondingly, the seasonal ozone depletion in the Antarctic. The geo-effective solar wind impacts on the atmospheric wind system in the entire Southern Polar region, and influences the dynamics of the Southern Oscillation (ENSO).В обзоре обобщены экспериментальные данные о влиянии космической погоды на земную атмосферу. Показано, что высокоэнергичные солнечные протоны (SPE) оказывают мощное воздействие на фотохимические процессы в полярных областях и, соответственно, на атмосферную циркуляцию и планетарную облачность. Вариации солнечного УФ-излучения моделируют скорость спуска зональных ветров в экваториальной стратосфере в ходе квазидвухлетней осцилляции (QBO) и контролируют, таким образом, общую продолжительность (период) QBO цикла и, соответственно, вариации общего содержания озона в Антарктике. Геоэффективный солнечный ветер воздействует на систему катабатических ветров во всей южной полярной области и влияет на динамику южной осцилляции (ENSO)

Magnetic local time dependence of geomagnetic disturbances contributing to the AU and AL indices

The Auroral Electrojet (AE) indices, which are composed of four indices (AU, AL, AE, and AO), are calculated from the geomagnetic field data obtained at 12 geomagnetic observatories that are located in geomagnetic latitude (GMLAT) of 61.7°-70°. The indices have been widely used to study magnetic activity in the auroral zone. In the present study, we examine magnetic local time (MLT) dependence of geomagnetic field variations contributing to the AU and AL indices. We use 1-min geomagnetic field data obtained in 2003. It is found that both AU and AL indices have two ranges of MLT (AU: 15:00-22:00MLT, ~06:00 MLT; and AL: ~02:00 MLT, 09:00-12:00 MLT) contributing to the index during quiet periods and one MLT range (AU: 15:00-20:00MLT, and AL: 00:00-06:00 MLT) during disturbed periods. These results are interpreted in terms of various ionospheric current systems, such as, Sqp, Sq, and DP2