669 research outputs found

    A note on the Weibel instability and thermal fluctuations

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    The thermal fluctuation level of the Weibel instability is recalculated. It is shown that the divergence of the fluctuations at long wavelengths, i.e. the Weibel infrared catastrophe, never occurs. At large wavelengths the thermal fluctuation level is terminated by the presence of even the smallest available stable thermal anisotropy. Weibel fields penetrate only one skin depth into the plasma. When excited inside, they cause layers of antiparallel fields of skin depth width and vortices which may be subject to reconnection.Comment: 4 pages, 2 figures, accepted by Ann Geophy

    Collisionless reconnection: Mechanism of self-ignition in thin current sheets

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    The spontaneous onset of magnetic reconnection in thin collisionless current sheets is shown to result from a thermal-anisotropy driven magnetic Weibel-mode, generating seed-magnetic field {\sf X}-points in the centre of the current layer.Comment: 8 pages, 6 figures, prepared for Annales Geophysica

    Ultrarelativistic generalized Lorentzian thermodynamics and the differential cosmic ray energy flux

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    We apply the ultrarelativistic generalized Lorentzian quasi-equilibrium thermodynamic energy distribution to the energy spectrum of galactic cosmic ray fluxes. The inferred power law slopes contain a component which evolves with cosmic ray energy in steps of thirds, resembling the sequence of structure functions in fully developed Kolmogorov turbulence. Within the generalized thermodynamics the chemical potential can be estimated from the deviation of the fluxes at decreasing energy. Both may throw some light on the cosmic ray acceleration mechanism to very high energies.Comment: 7 pages, 2 figures, prepared for a Meeting on Cosmic Rays and Power Law Tail

    Kinetic theory of information -- the dynamics of information

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    A kinetic approach to the notion of information is proposed, based on Liouville kinetic theory. The general kinetic equation for the evolution of the N-particle information IN\mathcal{I}_N in a Hamiltonian system of large particle number N1N\gg 1 is obtained. It is shown that the NN-particle information is strictly conserved. Defining reduced particle number information densities in phase space should be possible to obtain a kinetic equation for the ordinary one-particle information I1I\mathcal{I}_1\equiv \mathcal{I} following the Bogoliubov prescription. The kinetic equation for I\mathcal{I} is a kind of generalized Boltzmann equation with interaction term depending on the hierarchy of reduced informations. This term in its general form is the most general expression for the Kolmogorov entropy rate of evolution of the information.Comment: 5 pages, no figures, accepted in Front. Phy

    The mirror mode: A "superconducting'' space plasma analogue

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    We examine the physics of the magnetic mirror mode in its final state of saturation, the thermodynamic equilibrium, to demonstrate that the mirror mode is the analogue of a superconducting effect in a classical anisotropic-pressure space plasma. Two different spatial scales are identified which control the behaviour of its evolution. These are the ion inertial scale λim(τ)\lambda_{im}(\tau) based on the excess density Nm(τ)N_m(\tau) generated in the mirror mode, and a correlation length. This can be either the Debye length, the ion gyro-radius, or a turbulent correlation length. The mirror mode equilibrium structure under saturation is determined by the Landau-Ginzburg ratio of these two length scales. Mirror modes then behave like type II superconductors, naturally giving rise to chains of local depletions of the magnetic field of the kind observed in the mirror mode, providing the plasma a short scale magnetic bubble texture. This might be important in the study of magnetic turbulence in plasmas.Comment: 13 pages, 2 figure, Discussion paper, to appear in Ann. Geophy
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