631 research outputs found

    Effect of EMIC waves on relativistic and ultrarelativistic electron populations: Ground-based and Van Allen Probes observations

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    Abstract We study the effect of electromagnetic ion cyclotron (EMIC) waves on the loss and pitch angle scattering of relativistic and ultrarelativistic electrons during the recovery phase of a moderate geomagnetic storm on 11 October 2012. The EMIC wave activity was observed in situ on the Van Allen Probes and conjugately on the ground across the Canadian Array for Real-time Investigations of Magnetic Activity throughout an extended 18 h interval. However, neither enhanced precipitation of \u3e0.7 MeV electrons nor reductions in Van Allen Probe 90° pitch angle ultrarelativistic electron flux were observed. Computed radiation belt electron pitch angle diffusion rates demonstrate that rapid pitch angle diffusion is confined to low pitch angles and cannot reach 90°. For the first time, from both observational and modeling perspectives, we show evidence of EMIC waves triggering ultrarelativistic (~2-8 MeV) electron loss but which is confined to pitch angles below around 45° and not affecting the core distribution. Key Points EMIC wave activity is not associated with precipitation of MeV electrons EMIC waves do not deplete the ultra-relativistic belt down to 90° EMIC waves cause loss of low pitch angle electrons with energies ~2-8 MeV

    Organization of innovative project management on the base of multimode modeling of probabilities mixture of labor processes

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    © 2014, Mediterranean Center of Social and Educational Research. All rights reserved. In this study we suggest an approach to the organization of innovative projects management based on multimode modeling of probabilities mixture of labor processes. The proposed model allows managers to optimize the control actions influence on separate labor processes for achieving the innovative project result in the minimum time. Organization of management on the basis of the proposed model minimizes the risks of management bureaucracy and labor processes uncontrollability

    Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts.

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    The dipole configuration of the Earth's magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes

    Competing source and loss mechanisms due to wave-particle interactions in Earth’s outer radiation belt during the 30 September to 3 October 2012 geomagnetic storm

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    Abstract Drastic variations of Earth’s outer radiation belt electrons ultimately result from various competing source, loss, and transport processes, to which wave-particle interactions are critically important. Using 15 spacecraft including NASA’s Van Allen Probes, THEMIS, and SAMPEX missions and NOAA’s GOES and POES constellations, we investigated the evolution of the outer belt during the strong geomagnetic storm of 30 September to 3 October 2012. This storm’s main phase dropout exhibited enhanced losses to the atmosphere at L*\u3c 4, where the phase space density (PSD) of multi-MeV electrons dropped by over an order of magnitude in1 MeV electrons and energetic protons, SAMPEX \u3e1 MeV electrons, and ground observations of band-limited Pc1-2 wave activity, we show that this sudden loss was consistent with pitch angle scattering by electromagnetic ion cyclotron waves in the dusk magnetic local time sector at 3\u3c L*\u3c 4. At 4\u3c L*\u3c 5, local acceleration was also active during the main and early recovery phases, when growing peaks in electron PSD were observed by both Van Allen Probes and THEMIS. This acceleration corresponded to the period when IMF Bz was southward, the AE index was \u3e300 nT, and energetic electron injections and whistler-mode chorus waves were observed throughout the inner magnetosphere for \u3e12 h. After this period, Bz turned northward, and injections, chorus activity, and enhancements in PSD ceased. Overall, the outer belt was depleted by this storm. From the unprecedented level of observations available, we show direct evidence of the competitive nature of different wave-particle interactions controlling relativistic electron fluxes in the outer radiation belt

    Investigation of EMIC wave scattering as the cause for the BARREL 17 January 2013 relativistic electron precipitation event: A quantitative comparison of simulation with observations

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    Abstract Electromagnetic ion cyclotron (EMIC) waves were observed at multiple observatory locations for several hours on 17 January 2013. During the wave activity period, a duskside relativistic electron precipitation (REP) event was observed by one of the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) balloons and was magnetically mapped close to Geostationary Operational Environmental Satellite (GOES) 13. We simulate the relativistic electron pitch angle diffusion caused by gyroresonant interactions with EMIC waves using wave and particle data measured by multiple instruments on board GOES 13 and the Van Allen Probes. We show that the count rate, the energy distribution, and the time variation of the simulated precipitation all agree very well with the balloon observations, suggesting that EMIC wave scattering was likely the cause for the precipitation event. The event reported here is the first balloon REP event with closely conjugate EMIC wave observations, and our study employs the most detailed quantitative analysis on the link of EMIC waves with observed REP to date. Key PointsQuantitative analysis of the first balloon REP with closely conjugate EMIC wavesOur simulation suggests EMIC waves to be a viable cause for the REP eventThe adopted model is proved to be applicable to simulating the REP event

    Экономический потенциал Республики Беларусь после присоединения к ШОС: преимущества и возможности

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    In the era of globalization, integration groupings have become an important tool for the development of many countries in the world economy. They contribute to the formation of close economic ties and coordination of foreign trade between the participants, which in turn has a favorable effect on the development of the national economy of the country. Participation in integration associations is of great importance for the development of Belarus’ economy and increasing its role in the international arena. Membership in the SCO opens up new prospects for the country and provides an opportunity to expand cooperation with other countries of the Asian region. Once Belarus becomes a full-fledged member of the association, the country will have new ways to develop its potential in various areas, including the economy, logistics, transport, security, culture, education, healthcare, tourism, industrial and agricultural sector, science, as well as experience in international multilateral cooperation. The article is devoted to the topic of assessing the potential of joining the Shanghai Cooperation Organization integration association of the Republic of Belarus. In order to assess the prospects of economic cooperation more accurately, the authors conducted an econometric analysis using a modified version of the traditional gravity model of Belarus’ foreign trade with the member countries. As a result, the authors have identified the most significant factors influencing the volume of trade with the member countries. By analyzing the ratio of calculated indicators to the actual level of exports and imports, the authors made a conclusion about the level of realization of trade potential with the SCO countries. As a consequence, the authors proposed possible ways to implement trade by analyzing the commodity structure of foreign trade flows of the Republic of Belarus with the members of the integration association.В эпоху глобализации интеграционные группировки стали важным инструментом для развития множества стран в мировом хозяйстве. Они способствуют формированию тесных экономических связей и координации внешней торговли между участниками, что, в свою очередь, благоприятно сказывается на развитии национальной экономики страны. Участие в интеграционных объединениях имеет большое значение для развития экономики Беларуси и увеличения ее роли на международной арене. Вступление в ШОС открывает новые перспективы для страны и дает возможность расширять кооперацию с другими странами Азиатского региона. После становления Беларуси полноправным участником объединения перед страной откроются новые пути развития потенциала в различных сферах, включая экономику, логистику, транспорт, безопасность, культуру, образование, здравоохранение, туризм, промышленный и сельскохозяйственный сектор, науку, а также опыт международного многостороннего сотрудничества. Исследование посвящено оценке потенциала вступления Республики Беларусь в интеграционное объединение Шанхайской организации сотрудничества. Для более точной оценки перспектив экономического сотрудничества, авторами был проведен эконометрический анализ с использованием модифицированной версии традиционной гравитационной модели внешней торговли Беларуси со странами-участницами. В результате авторами были выявлены самые значимые факторы влияния на объем торговли со странами-участницами. В результате анализа отношения расчетных показателей к фактическому уровню экспорта и импорта авторы сделали вывод об уровне реализации торгового потенциала со странами ШОС, вследствие чего предложены возможные пути реализации торговли с помощью анализа товарной структуры потоков внешней торговли Республики Беларусь с участницами интеграционного объединения

    Observations of coincident EMIC wave activity and dusk-side energetic electron precipitation on 18-19 January 2013

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    Electromagnetic ion cyclotron (EMIC) waves have been suggested to be a cause of radiation belt electron loss to the atmosphere. Here simultaneous, magnetically conjugate measurements are presented of EMIC wave activity, measured at geosynchronous orbit and on the ground, and energetic electron precipitation, seen by the BARREL balloon campaign, on two consecutive days in January 2013. Multiple bursts of precipitation were observed on the dusk-side of the magnetosphere at the end of 18 Jan and again late on 19 Jan, concurrent with particle injections, substorm activity, and enhanced magnetospheric convection. The structure, timing, and spatial extent of the waves are compared to those of the precipitation during both days to determine when and where EMIC waves cause radiation belt electron precipitation. The conjugate measurements presented here provide observational support of the theoretical picture of dusk-side interaction of EMIC waves and MeV electrons leading to radiation belt loss

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

    Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

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    Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations

    Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

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    The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured
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