Biblio

Found 4 results
Filters: Author is Albert, J. M.  [Clear All Filters]
2014
Authors: Ripoll J.-F., Albert J M, and Cunningham G. S.
Title: Electron lifetimes from narrowband wave-particle interactions within the plasmasphere
Abstract: This paper is devoted to the systematic study of electron lifetimes from narrowband wave-particle interactions within the plasmasphere. It relies on a new formulation of the bounce-averaged quasi-linear pitch angle diffusion coefficients parameterized by a single frequency, ω, and wave normal angle, θ. We first show that the diffusion coefficients scale with ω/Ωce, where Ωce is the equatorial electron gyrofrequency, and that maximal pitch angle diffusion occurs along the line α0 = π/2–θ, where α0 is the equatorial pitch angle. Lifetimes are computed for L shell values in the range [1.5, 3.5] and energies, E, in the range [0.1, 6] MeV as a function of frequency and wave normal angle. The maximal pitch angle associated with a given lifetime is also given, revealing the frequen. . .
Date: 11/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020217 Available at: http://doi.wiley.com/10.1002/2014JA020217
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2005
Authors: Albert J M
Title: Evaluation of quasi-linear diffusion coefficients for whistler mode waves in a plasma with arbitrary density ratio
Abstract: Techniques are presented for efficiently evaluating quasi-linear diffusion coefficients for whistler mode waves propagating according to the full cold plasma index of refraction. In particular, the density ratio ωpe/Ωe can be small, which favors energy diffusion. This generalizes an approach, previously used for high-density hiss and electromagnetic ion cyclotron waves, of identifying (and omitting) ranges of wavenormal angle θ that are incompatible with cyclotron resonant frequencies ω occurring between sharp cutoffs of the modeled wave frequency spectrum. This requires a detailed analysis of the maximum and minimum values of the refractive index as a function of ω and θ, as has previously been performed in the high-density approximation. Sample calculations show the effect of low-d. . .
Date: 03/2005 Publisher: Journal of Geophysical Research DOI: 10.1029/2004JA010844 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2004JA010844/abstract
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2003
Authors: Albert J M
Title: Evaluation of quasi-linear diffusion coefficients for EMIC waves in a multispecies plasma
Abstract: Quasi-linear velocity-space diffusion coefficients due to L-mode electromagnetic ion cyclotron (EMIC) waves are considered in a multispecies plasma. It is shown, with slight approximations to exact cold plasma theory, that within EMIC pass bands the index of refraction is a monotonically increasing function of frequency. Analytical criteria are then derived which identify ranges of latitude, wavenormal angle, and resonance number consistent with resonance in a prescribed wave population. This leads to computational techniques which allow very efficient calculation of the diffusion coefficients, along the lines previously developed for whistler and ion cyclotron waves in an electron-proton plasma. The techniques are applied to radiation belt electrons at L = 4, for EMIC waves in the hydroge. . .
Date: 06/2003 Publisher: Journal of Geophysical Research DOI: 10.1029/2002JA009792 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2002JA009792/abstract
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2000
Authors: Brautigam D H, and Albert J M
Title: Radial diffusion analysis of outer radiation belt electrons during the October 9, 1990, magnetic storm
Abstract: The response of outer radiation belt relativistic electrons to the October 9, 1990, magnetic storm is analyzed in detail using a radial diffusion model and data from the Combined Release and Radiation Effects Satellite (CRRES) and the Los Alamos National Laboratory (LANL) geosynchronous satellite 1989-046. Electron measurements are expressed in terms of phase space density as a function of the three adiabatic invariants determined from CRRES magnetic field data and the Tsyganenko 1989 Kp-dependent magnetic field model. The radial diffusion model is implemented with a time-dependent radial diffusion coefficient parameterized by Kp, and a time-dependent outer boundary condition scaled by geosynchronous electron data. The results show that radial diffusion propagates outer boundary variations. . .
Date: 01/2000 Publisher: Journal of Geophysical Research Pages: 291 DOI: 10.1029/1999JA900344 Available at: http://onlinelibrary.wiley.com/doi/10.1029/1999JA900344/full
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