2,117 research outputs found
Evolution of kinklike fluctuations associated with ion pickup within reconnection outflows in the Earth's magnetotail
Magnetic reconnection (MR) in Earth's magnetotail is usually followed by a
systemwide redistribution of explosively released kinetic and thermal energy.
Recently, multispacecraft observations from the THEMIS mission were used to
study localized explosions associated with MR in the magnetotail so as to
understand subsequent Earthward propagation of MR outbursts during substorms.
Here we investigate plasma and magnetic field fluctuations/structures
associated with MR exhaust and ion-ion kink mode instability during a well
documented MR event. Generation, evolution and fading of kinklike oscillations
are followed over a distance of 70 000 km from the reconnection site in the
midmagnetotail to the more dipolar region near the Earth. We have found that
the kink oscillations driven by different ion populations within the outflow
region can be at least 25 000 km from the reconnection site.Comment: 11 pages, 4 figure
The backbone of democracy. The metainstitutional basis of modern society
The article deals with the "minimal configuration" of social institutions that ensure sustainable development not by adapting to the environment (the adaptive behaviour characteristic of traditional societies), but through uninterrupted generation and implementation of innovations that transform environment to meet the changing needs of humankind. This type of active adaptive behaviour characteristic of modern society could not be maintained in the absence of three basic "metainstitutions" of modernity, viz. 1) science, 2) the banking and exchange system, 3) institutions of representative democracy (parliaments), plus three "support institutions": 4) free press (mass media), 5) rational bureaucracy, 6) independent judiciaryyesBelgorod State National Research Universit
Dynamical response of the magnetotail to changes of the solar wind direction: an MHD modeling perspective
We performed global MHD simulations to investigate the magnetotail response to the solar wind directional changes (<I>V<sub>z</sub></I>-variations). These changes, although small, cause significant variations of the neutral sheet shape and location even in the near and middle tail regions. They display a complicated temporal response, in which ~60 to 80% of the final shift of the neutral sheet in <I>Z</I> direction occurs within first 10–15 min (less for faster solar wind), whereas a much longer time (exceeding half hour) is required to reach a new equilibrium. The asymptotic equilibrium shape of the simulated neutral sheet is consistent with predictions of Tsyganenko-Fairfield (2004) empirical model. To visualize a physical origin of the north-south tail motion we compared the values of the total pressure in the northern and southern tail lobes and found a considerable difference (10–15% for only 6&deg; change of the solar wind direction used in the simulation). That difference builds up during the passage of the solar wind directional discontinuity and is responsible for the vertical shift of the neutral sheet, although some pressure difference remains in the near tail even near the new equilibrium. Surprisingly, at a given tailward distance, the response was found to be first initiated in the tail center (the "leader effect"), rather than near the flanks, which can be explained by the wave propagation in the tail, and which may have interesting implications for the substorm triggering studies. The present results have serious implications for the data-based modeling, as they place constraints on the accuracy of tail magnetic configurations to be derived for specific events using data of multi-spacecraft missions, e.g. such as THEMIS
Visualizing Pure Quantum Turbulence in Superfluid He: Andreev Reflection and its Spectral Properties
Superfluid He-B in the zero-temperature limit offers a unique means of
studying quantum turbulence by the Andreev reflection of quasiparticle
excitations by the vortex flow fields. We validate the experimental
visualization of turbulence in He-B by showing the relation between the
vortex-line density and the Andreev reflectance of the vortex tangle in the
first simulations of the Andreev reflectance by a realistic 3D vortex tangle,
and comparing the results with the first experimental measurements able to
probe quantum turbulence on length scales smaller than the inter-vortex
separation.Comment: 5 pages, 4 figures, and Supplemental Material (2 pages, 2 figures
Quantitative magnetotail characteristics of different magnetospheric states
Quantitative relationships allowing one to compute the lobe magnetic field, flaring angle and tail radius, and to evaluate magnetic flux based on solar wind/IMF parameters and spacecraft position are obtained for the middle magnetotail, <i>X</i>=(–15,–35)<i>R<sub>E</sub></i>, using 3.5 years of simultaneous Geotail and Wind spacecraft observations. For the first time it was done separately for different states of magnetotail including the substorm onset (SO) epoch, the steady magnetospheric convection (SMC) and quiet periods (Q). In the explored distance range the magnetotail parameters appeared to be similar (within the error bar) for Q and SMC states, whereas at SO their values are considerably larger. In particular, the tail radius is larger by 1–3 <i>R<sub>E</sub></i> at substorm onset than during Q and SMC states, for which the radius value is close to previous magnetopause model values. The calculated lobe magnetic flux value at substorm onset is ~1GWb, exceeding that at Q (SMC) states by ~50%. The model magnetic flux values at substorm onset and SMC show little dependence on the solar wind dynamic pressure and distance in the tail, so the magnetic flux value can serve as an important discriminator of the state of the middle magnetotail.<br><br> <b>Key words.</b> Magnetospheric physics (solar windmagnetosphere- interactions, magnetotail, storms and substorms
β-Polymorph of phenazepam: a powder study
The title compound [systematic name: 7-bromo-5-(2-chlorophenyl)-1H-1,4-benzodiazepin-2(3H)-one] (β-polymorph), C15H10BrClN2O, has been obtained via cryomodification of the known α-polymorph of phenazepam [Karapetyan et al. (1979 ▶). Bioorg. Khim.
5, 1684–1690]. In both polymorphs, the molecules, which differ only in the dihedral angles between the aromatic rings [75.4 (2)° and 86.2 (3)° in the α- and β-polymorphs, respectively], are linked into centrosymmetric dimers via N—H⋯O hydrogen bonds. In the crystal structure of the β-polymorph, weak intermolecular C—H⋯O hydrogen bonds further link these dimers into layers parallel to bc plane
Casimir eigenvalues for universal Lie algebra
For two different natural definitions of Casimir operators for simple Lie
algebras we show that their eigenvalues in the adjoint representation can be
expressed polynomially in the universal Vogel's parameters and give explicit formulae for the generating functions of these
eigenvalues.Comment: Slightly revised versio
On Spin Calogero-Moser system at infinity
We present a construction of a new integrable model as an infinite limit of Calogero models of N particles with spin. It is implemented in the multicomponent Fock space. Explicit formulas for Dunkl operators, the Yangian generators in the multicomponent Fock space are presented. The classical limit of the system is examined
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