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Field Generation (field + generation)
Selected AbstractsAnomalous diffusion and radial electric field generation due to edge plasma turbulenceCONTRIBUTIONS TO PLASMA PHYSICS, Issue 1-3 2004R. Pánek No abstract is available for this article. [source] Baryon loading and the Weibel instability in gamma-ray burstsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006M. Fiore ABSTRACT The dynamics of two counter-streaming electron,positron,ion unmagnetized plasma shells with zero net charge is analysed in the context of magnetic field generation in gamma-ray burst internal shocks due to the Weibel instability. The effects of large thermal motion of plasma particles, arbitrary mixture of plasma species and space charge effects are taken into account. We show that, although thermal effects slow down the instability, baryon loading leads to a non-negligible growth rate even for large temperatures and different shell velocities, thus guaranteeing the robustness and the occurrence of the Weibel instability for a wide range of scenarios. [source] Algorithms for vector field generation in mass consistent modelsNUMERICAL METHODS FOR PARTIAL DIFFERENTIAL EQUATIONS, Issue 4 2010Ciro Flores Abstract Diagnostic models in meteorology are based on the fulfillment of some time independent physical constraints as, for instance, mass conservation. A successful method to generate an adjusted wind field, based on mass conservation equation, was proposed by Sasaki and leads to the solution of an elliptic problem for the multiplier. Here we study the problem of generating an adjusted wind field from given horizontal initial velocity data, by two ways. The first one is based on orthogonal projection in Hilbert spaces and leads to the same elliptic problem but with natural boundary conditions for the multiplier. We derive from this approach the so called E,algorithm. An innovative alternative proposal is obtained from a second approach where we consider the saddle,point formulation of the problem,avoiding boundary conditions for the multiplier, and solving this problem by iterative conjugate gradient methods. This leads to an algorithm that we call the CG,algorithm, which is inspired from Glowinsk's approach to solve Stokes,like problems in computational fluid dynamics. Finally, the introduction of new boundary conditions for the multiplier in the elliptic problem generates better adjusted fields than those obtained with the original boundary conditions. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010 [source] Magnetic fields in the early UniverseASTRONOMISCHE NACHRICHTEN, Issue 1 2010K. Subramanian Abstract We give a pedagogical introduction to two aspects of magnetic fields in the early Universe. We first focus on how to formulate electrodynamics in curved space time, defining appropriate magnetic and electric fields and writing Maxwell equations in terms of these fields. We then specialize to the case of magnetohydrodynamics in the expanding Universe. We emphasize the usefulness of tetrads in this context. We then review the generation of magnetic fields during the inflationary era, deriving in detail the predicted magnetic and electric spectra for some models. We discuss potential problems arising from back reaction effects and from the large variation of the coupling constants required for such field generation (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||