4,476 research outputs found

    Solar-Terrestrial Simulations of CMEs with a Realistic Initiation Mechanism: Case Study for Active Region 10069

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    Most simulations of coronal mass ejections (CMEs) to date either focus on the interplanetary propagation of a giant plasma "blob" without paying too much attention to its origin and to the formation process or they focus on the complex evolution of the coronal magnetic field due to (sub-)photospheric motions which result in an eruption. Here, we present global simulations of CMEs where coronal motions are used to produce a realistic evolution of the coronal magnetic field and cause an eruption. We focus on active region 10069, which produced a number of eruptions in late August 2002, including the August 24, 2002 CME - a fast (~2000 km/s) eruption originating from W81-, as well as a slower eruption on August 22, 2002 (originating from W62). Using a three-dimensional magneto-hydrodynamic (MHD) simulation of these ejections with the Space Weather Modeling Framework (SWMF), we show how a realistic initiation mechanism enables us to study the deflection of the CME in the corona and in the heliosphere. Reconnection of the erupting magnetic field with that of neighboring streamers and active regions modify the solar connectivity of the field lines connecting to Earth and change the expected solar energetic particle fluxes. Comparing the results at 1 AU of our simulations with in situ observations by the ACE spacecraft, we propose an alternate solar origin for the shock wave observed at L1 on August 26.Comment: 4 pages, 2 figures, refereed proceedings for Solar Wind 1

    Charge transfer transitions in the photoluminescence spectra of Zn1-xMexO (Me = Mn, Ni, Co) oxide compounds

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    Crystals of Zn1-xCoxO and Zn1-xNixO are studied by photoluminescence at temperatures of 8 and 90 K. By resolving the spectra into sums of gaussian distributions and using the known positions of donor and acceptor levels of 3d-impurities relative to the edges of the allowed bands, the observed peaks in the photoluminescence spectra are interpreted in terms of radiative recombination through donor and acceptor levels of nickel and cobalt ions. These results are compared with previously observed features of the photoluminescence spectra of Zn1-xMnxO crystals. © 2013 American Institute of Physics

    Understanding Anomalous Transport in Intermittent Maps: From Continuous Time Random Walks to Fractals

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    We show that the generalized diffusion coefficient of a subdiffusive intermittent map is a fractal function of control parameters. A modified continuous time random walk theory yields its coarse functional form and correctly describes a dynamical phase transition from normal to anomalous diffusion marked by strong suppression of diffusion. Similarly, the probability density of moving particles is governed by a time-fractional diffusion equation on coarse scales while exhibiting a specific fine structure. Approximations beyond stochastic theory are derived from a generalized Taylor-Green-Kubo formula.Comment: 4 pages, 3 eps figure

    Periods of activity cycles in late-type stars

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    The mean magnetic field dynamo theory is utilized to obtain the qualitative dependence of the period of activity on the angular velocity of rotation for stars with sufficiently extensive convective shells. The dependence of the cycle period on the spectral class is also discussed

    Phase Transitions in liquid Helium 3

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    The phase transitions of liquid Helium 3 are described by truncations of an exact nonperturbative renormalization group equation. The location of the first order transition lines and the jump in the order parameter are computed quantitatively. At the triple point we find indications for partially universal behaviour. We suggest experiments that could help to determine the effective interactions between fermion pairs.Comment: 4 pages, 6 figures, LaTe

    Pseudo-epsilon expansion and the two-dimensional Ising model

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    Starting from the five-loop renormalization-group expansions for the two-dimensional Euclidean scalar \phi^4 field theory (field-theoretical version of two-dimensional Ising model), pseudo-\epsilon expansions for the Wilson fixed point coordinate g*, critical exponents, and the sextic effective coupling constant g_6 are obtained. Pseudo-\epsilon expansions for g*, inverse susceptibility exponent \gamma, and g_6 are found to possess a remarkable property - higher-order terms in these expansions turn out to be so small that accurate enough numerical estimates can be obtained using simple Pade approximants, i. e. without addressing resummation procedures based upon the Borel transformation.Comment: 4 pages, 4 tables, few misprints avoide

    Post-Socialist Transformation of Central and Eastern Europe at the Turn of the Century: Regional Development and Economic Inequality

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    The evolution of socio-economic systems is non-linear, it includes both the periods of smooth changes and subsequent abrupt transformational leaps. The overall structure of new prospects opens as early as at the stage of emerging evolutionary processes, and their forecast requires to analyze the historical premises and risks that are closely associated with the change of public attitudes. With the collapse of the Soviet Union, the newly independent states went through a transformational and evolutionary development stage that led them from a regional economy (since they actually had been the regions) to the national economy, while the countries in Central and Eastern Europe experienced a dramatic drift towards the European Union. This paper examines the results of almost 25-year-long transformation of these countries. The new states that emerged following the collapse of the Soviet Union went through three types of transformation. First, there were transformations on the ideological level. The transformations of the second type were purely economic. The third type can be described as institutional (including structural and financial) transformation. It has been demonstrated that one of the important reasons for modest economic performance in the post-Soviet space was the fact that the new states ignored and did not use the principles of regional policy and regional modernization in their state-building practice. A characteristic feature in the socio-economic evolution of Eastern Europe after 1990 was a sharply emphasized process of stratification and social differentiation occurring against the backdrop of insufficiently strong middle class and the polarization of income levels in different regions. The growing polarization of income levels in different regions represents the dominant trend of rising economic inequality.This research has been conducted with the support of the Russian Science Foundation (the Grant No. 14–28–00065) "Structural and Cyclical Paradigm of Economic and Technological Renewal of Macro-Social Systems (World and Russia in the First Half of the 21st century).
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