Field line dependence of magnetospheric electron density

Denton, R. E.; Goldstein, J.; Menietti, J. D.

doi:10.1029/2002gl015963

Cited by 73 publications

(128 citation statements)

References 8 publications

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“…We assume in equation (A1) that the density remains roughly constant along a geomagnetic field line up to a maximum latitude of interaction of about 35 [Denton et al, 2002;Horne et al, 2005]. We use subscript "0" for equatorial values of variables.…”

Section: Discussionmentioning

confidence: 99%

Timescales for electron quasi‐linear diffusion by parallel and oblique lower‐band chorus waves

et al. 2012

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[1] The loss of relativistic electrons from the Earth's radiation belts can be described in terms of the quasi-linear pitch angle diffusion by cyclotron-resonant waves, provided that their frequency spectrum is broad enough. Chorus waves at large wave-normal angles with respect to the magnetic field are often present in CLUSTER and THEMIS measurements in the outer belt at moderate to high latitudes. An approximate analytical formulation of diffusion coefficients has been derived in the low-frequency limit, leading to a simplified analytical expression of diffusion coefficients and lifetimes for energetic trapped electrons. Large values of the wave-normal angles between the Gendrin and resonance angles are shown to induce important increases in diffusion, thereby strongly reducing the particle lifetimes (by almost two orders of magnitude). The analytical diffusion coefficients and lifetimes obtained here are found to be in a good agreement with full numerical calculations based on CLUSTER chorus waves measurements in the outer belt for electron energies ranging from 100 keV to 2 MeV. Such very oblique chorus waves could contribute to a predominantly perpendicular anisotropy of the global equatorial electron population on the dayside and to a relative isotropization at low energy under disturbed conditions. It is also suggested that they might play a significant role in pulsating auroras.

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Section: Discussionmentioning

confidence: 99%

Timescales for electron quasi‐linear diffusion by parallel and oblique lower‐band chorus waves

et al. 2012

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“…In studies based on data from the POLAR spacecraft (Denton et al 2002a(Denton et al , 2002b), a power law dependence was assumed with respect to the geocentric radius,…”

Section: Field Line Dependence Of Electron Density From In Situ Datamentioning

confidence: 99%

Augmented Empirical Models of Plasmaspheric Density and Electric Field Using IMAGE and CLUSTER Data

et al. 2009

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Empirical models for the plasma densities in the inner magnetosphere, including plasmasphere and polar magnetosphere, have been in the past derived from in situ measurements. Such empirical models, however, are still in their initial phase compared to magnetospheric magnetic field models. Recent studies using data from CRRES, POLAR, and IMAGE have significantly improved empirical models for inner-magnetospheric plasma and mass densities. Comprehensive electric field models in the magnetosphere have been developed using radar and in situ observations at low altitude orbits. To use these models at high altitudes one needs to rely strongly on the assumption of equipotential magnetic field lines. 232 B.W. Reinisch et al.Direct measurements of the electric field by the CLUSTER mission have been used to derive an equatorial electric field model in which reliance on the equipotential assumption is less. In this paper we review the recent progress in developing empirical models of plasma densities and electric fields in the inner magnetosphere with emphasis on the achievements from the IMAGE and CLUSTER missions. Recent results from other satellites are also discussed when they are relevant.

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“…In this work, we simply use B 0x = Àx(dB 0z /dz)/2 and B 0y = Ày(dB 0z /dz)/2. The cold electron density is given by n e = n e0 cos À4 l, following Denton et al [2002], with n e0 = 10 cm À3 .…”

Section: Effects Of Amplitude Modulation On Nonlinear Interactionsmentioning

confidence: 99%

Effects of amplitude modulation on nonlinear interactions between electrons and chorus waves

Tao

Bortnik

Thorne

et al. 2012

Geophysical Research Letters

117

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[1] The effects of amplitude modulation on nonlinear interactions between a parallel propagating chorus wave packet and electrons in a dipole field are investigated in this work using a test particle code. Previous research used a single wave to model a chorus wave element, leading to nonlinear processes such as phase trapping and bunching when the wave amplitude was large enough. However, high resolution observations of chorus wave packets show a modulation of the wave amplitude, forming the so-called chorus subpackets or subelements. Here we first extend a previous method to model a realistic chorus packet. Using the modeled chorus packet, we demonstrate directly that including the realistic amplitude modulation could significantly affect the behavior of resonant electrons. Our results suggest that the amplitude modulation should be considered in the quantitative treatment of interactions between electrons and chorus waves. Citation: Tao, X., J. Bortnik, R. M. Thorne, J. M. Albert, and W. Li (2012), Effects of amplitude modulation on nonlinear interactions between electrons and chorus waves, Geophys. Res. Lett., 39, L06102,

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Field line dependence of magnetospheric electron density

Cited by 73 publications

References 8 publications

Timescales for electron quasi‐linear diffusion by parallel and oblique lower‐band chorus waves

Timescales for electron quasi‐linear diffusion by parallel and oblique lower‐band chorus waves

Augmented Empirical Models of Plasmaspheric Density and Electric Field Using IMAGE and CLUSTER Data

Effects of amplitude modulation on nonlinear interactions between electrons and chorus waves

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