1,169 research outputs found

    Magnetic fluctuation and cosmic ray diurnal variations

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    A unified theory of cosmic ray diurnal variations has been proposed in which the first 3 harmonics of the cosmic ray daily variation all results from a single anisotropy produced by the combined effects of adiabatic focusing and anisotropic pitch angle scattering. The theoretical description of steady state cosmic ray anisotropies are simplified and improved. Preliminary results of a study of correlations between cosmic ray diurnal variations and the fluctuation characteristics of the interplanetary magnetic field are presented and discussed in light of the theory

    An Investigation of the Concept of Perfectionism as Target in the Writings of Ellen G. White

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    This thesis provides an examination of the concept of Perfectionism in the writings of Ellen G. White. During her lifetime, the topic was hotly debated in many of the churches, which may have influenced her teaching

    Exponential anisotropy of solar cosmic rays

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    On 16 February 1984 a flare on the Sun's invisible disk produced a large, highly anisotropic solar particle event. A technique, in which interplanetary scattering parameters are determined purely from the form of the particle anisotropy, is applied to energetic particle data from neutron monitors and the ICE spacecraft

    Magnetic helicity in magnetohydrodynamic turbulence with a mean magnetic field

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    A computational investigation of magnetic helicity of the fluctuatingmagnetic fieldHm in ideal and freely decaying three‐dimensional (3‐D) magnetohydrodynamics (MHD) in the presence of a uniform mean magnetic field is performed. It is shown that for ideal 3‐D MHDHm, which is a rugged invariant in the absence of a mean magnetic field [Frisch et al., J. Fluid Mech. 77, 796 (1975)], decays from its initial value and proceeds to oscillate about zero. The decay of Hm is shown to result from the presence of a new ‘‘generalized’’ helicity invariant, which includes contributions from the uniform magnetic field. The loss of invariance of Hm will diminish the effects of inverse transfer of Hm on freely decaying turbulence. This is demonstrated in a discussion of the selective decay relaxation process

    Turbulence transport throughout the heliosphere

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    We employ a turbulence transport model to compute distributions of turbulence throughout the heliosphere. The model determines the radial dependence of three (coupled) quantities that characterize interplanetary turbulence, the energy per unit mass, the cross helicity or Alfvénicity, and a similarity length scale. A fourth integrated quantity, the plasma temperature, is modified by heat deposition due to turbulent dissipation. The model includes advection, expansion, and reflection effects as well as the tendency toward dynamic alignment, and a von Kármán type dissipation function that represents decay of turbulence due to cascade to small scales. Two types of forcing are also featured, one a simple model of stream shear, and the other a driving in the outer heliosphere associated with wave energy injection due to pickup protons of interstellar origin. Parameters for the model have been tuned using observation data from Voyager and Ulysses. We analyze the constraining observations to provide boundary conditions and parameters that vary with heliocentric latitude, with some extrapolations. The fully assembled model permits the computation of the distribution of turbulence throughout the entire heliosphere, and we present solutions for several appropriate parameter sets

    Spin-polarization-induced structural selectivity in Pd3X_3X and Pt3X_3X (X=3dX=3d) compounds

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    Spin-polarization is known to lead to important {\it magnetic} and {\it optical} effects in open-shell atoms and elemental solids, but has rarely been implicated in controlling {\it structural} selectivity in compounds and alloys. Here we show that spin-polarized electronic structure calculations are crucial for predicting the correct T=0T=0 crystal structures for Pd3X_3X and Pt3X_3X compounds. Spin-polarization leads to (i) stabilization of the L12L1_2 structure over the DO22DO_{22} structure in Pt3_3Cr, Pd3_3Cr, and Pd3_3Mn, (ii) to the stabilization of the DO22DO_{22} structure over the L12L1_2 structure in Pd3_3Co and to (iii) ordering (rather than phase-separation) in Pt3_3Co and Pd3_3Cr. The results are analyzed in terms of first-principles local spin density calculations.Comment: 4 pages, REVTEX, 3 eps figures, to appear in PR
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