2,779 research outputs found

    Optimal time decay of the non cut-off Boltzmann equation in the whole space

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    In this paper we study the large-time behavior of perturbative classical solutions to the hard and soft potential Boltzmann equation without the angular cut-off assumption in the whole space \threed_x with \DgE. We use the existence theory of global in time nearby Maxwellian solutions from \cite{gsNonCutA,gsNonCut0}. It has been a longstanding open problem to determine the large time decay rates for the soft potential Boltzmann equation in the whole space, with or without the angular cut-off assumption \cite{MR677262,MR2847536}. For perturbative initial data, we prove that solutions converge to the global Maxwellian with the optimal large-time decay rate of O(t^{-\frac{\Ndim}{2}+\frac{\Ndim}{2r}}) in the L^2_\vel(L^r_x)-norm for any 2≤r≤∞2\leq r\leq \infty.Comment: 31 pages, final version to appear in KR

    Momentum Regularity and Stability of the Relativistic Vlasov-Maxwell-Boltzmann System

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    In the study of solutions to the relativistic Boltzmann equation, their regularity with respect to the momentum variables has been an outstanding question, even local in time, due to the initially unexpected growth in the post-collisional momentum variables which was discovered in 1991 by Glassey & Strauss \cite{MR1105532}. We establish momentum regularity within energy spaces via a new splitting technique and interplay between the Glassey-Strauss frame and the center of mass frame of the relativistic collision operator. In a periodic box, these new momentum regularity estimates lead to a proof of global existence of classical solutions to the two-species relativistic Vlasov-Boltzmann-Maxwell system for charged particles near Maxwellian with hard ball interaction.Comment: 23 pages; made revisions which were suggested by the referee; to appear in Comm. Math. Phy

    The Vlasov-Poisson-Landau System in Rx3\R^3_x

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    For the Landau-Poisson system with Coulomb interaction in Rx3\R^3_x, we prove the global existence, uniqueness, and large time convergence rates to the Maxwellian equilibrium for solutions which start out sufficiently close.Comment: 50 page

    Global Classical Solutions of the Boltzmann Equation with Long-Range Interactions and Soft Potentials

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    In this work we prove global stability for the Boltzmann equation (1872) with the physical collision kernels derived by Maxwell in 1866 for the full range of inverse power intermolecular potentials, r−(p−1)r^{-(p-1)} with p>2p>2. This completes the work which we began in (arXiv:0912.0888v1). We more generally cover collision kernels with parameters s∈(0,1)s\in (0,1) and γ\gamma satisfying γ>−(n−2)−2s\gamma > -(n-2)-2s in arbitrary dimensions Tn×Rn\mathbb{T}^n \times \mathbb{R}^n with n≥2n\ge 2. Moreover, we prove rapid convergence as predicted by the Boltzmann H-Theorem. When γ+2s≥0\gamma + 2s \ge 0, we have exponential time decay to the Maxwellian equilibrium states. When γ+2s<0\gamma + 2s < 0, our solutions decay polynomially fast in time with any rate. These results are constructive. Additionally, we prove sharp constructive upper and lower bounds for the linearized collision operator in terms of a geometric fractional Sobolev norm; we thus observe that a spectral gap exists only when γ+2s≥0\gamma + 2s \ge 0, as conjectured in Mouhot-Strain (2007).Comment: This file has not changed, but this work has been combined with (arXiv:0912.0888v1), simplified and extended into a new preprint, please see the updated version: arXiv:1011.5441v

    Wind speed statistics for Goldstone, California, anemometer sites

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    An exploratory wind survey at an antenna complex was summarized statistically for application to future windmill designs. Data were collected at six locations from a total of 10 anemometers. Statistics include means, standard deviations, cubes, pattern factors, correlation coefficients, and exponents for power law profile of wind speed. Curves presented include: mean monthly wind speeds, moving averages, and diurnal variation patterns. It is concluded that three of the locations have sufficiently strong winds to justify consideration for windmill sites
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