An empirical plasmasphere and trough density model: CRRES observations

Sheeley, B. W.; Moldwin, M. B.; Rassoul, H. K.; Anderson, R. R.

doi:10.1029/2000ja000286

Cited by 439 publications

(851 citation statements)

References 11 publications

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“…Second, this variation is similar to the density of the ionosphere at 2000 km, as given by the International Reference Ionosphere. Third, this variation is nearly identical with the trough density model recently proposed by Sheeley et al (2001) that was deduced from CRRES observations. For L = 6.6, they obtained (their Eq.…”

Section: Density Measurementssupporting

confidence: 71%

The local-time variation of the quiet plasmasphere: geosynchronous observations and kinetic theory

Reynolds

Ganguli

et al. 2003

Ann. Geophys.

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Abstract. The quiet-time structure of the plasmaspheric density was investigated using observations of the Los Alamos geosynchronous satellites, and these observations were compared with theoretical predictions of the quasi-static localtime variation by a kinetic model. It was found that the coupling to the ionosphere (via the local-time variation of the exobase) played a key role in determining the density structure at 6.6 R E . The kinetic model predicts that most of the local-time variation at geosynchronous orbit is due to the variation of the exobase parameters. During quiet times, when the convection electric field is dominated by the corotation field, the effects due to flux-tube convection are less prominent than those due to the exobase variation. In addition, the kinetic model predicts that the geosynchronous plasmaspheric density level is at most only 25% of saturation density, even when geomagnetic activity is low. The low night-time densities of the ionospheric footpoints, and the subsequent long trapping time scales, prevent the equatorial densities from reaching saturation.

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Section: Density Measurementssupporting

confidence: 71%

The local-time variation of the quiet plasmasphere: geosynchronous observations and kinetic theory

Reynolds

Ganguli

et al. 2003

Ann. Geophys.

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“…The wave amplitude of 10 pT is comparable to an observed chorus amplitude during substorms [Meredith et al, 2000] and that of 25 pT is a typical nightside chorus during the storm recovery phase [Li et al, 2007]. We use the empirical plasmaspheric trough density model given by Sheeley et al [2001] as the ambient density model. The calculation of the theoretical loss time scales is performed every 0.3 h MLT between 2.1 and 10.2 MLT, and we estimate the decay rates due to the pitch angle scattering by the chorus waves as the combination of the decay rates by the lower band and upper band chorus.…”

Section: Evaluation Of Theoretical Loss Time Scales Based On Pitch Anmentioning

confidence: 99%

Transport and loss of the inner plasma sheet electrons: THEMIS observations

et al. 2011

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[1] Using the electron data from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft measurements from 2007 to 2009, we derived global phase space density (PSD) distributions of plasma sheet electrons (2-100 eV/nT) to examine the transport process of the electrons to the inner magnetosphere and possible loss mechanisms of plasma sheet electrons during the convective transport. The inner boundaries of the electron plasma sheet were determined by the observed global distributions and compared with the Alfvén boundaries that were calculated by the sum of the simple corotation and convection electric field models. This comparison confirms the previous results that the large-scale convection electric field controls the electron transport to the inner magnetosphere. The gradual decrease in PSD is observed from the dawn to the dayside sector, indicating the existence of some loss mechanisms in the morning sector. The loss time scales estimated from the PSD distributions were compared with the theoretical ones based on the quasi-linear diffusion theory using an empirical wave model of whistler mode chorus. We also estimated the required wave amplitudes that can explain the estimated loss time scales. It is shown that whistler mode chorus has a sufficient power to scatter the plasma sheet electrons, and the required wave amplitudes are roughly consistent with the CRRES statistical survey of the chorus wave amplitude. We suggest that the loss of plasma sheet electrons in the morning sector is mainly induced by pitch angle scattering by whistler mode chorus.

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“…Since EMIC waves preferentially occur in the high-density regions overlapping with the hot anisotropic ions, we obtain the equatorial plasma density (N 0 ) values by using the plasmaspheric density model of Sheeley et al [2001] as follows:…”

Section: Model Descriptionmentioning

confidence: 99%

Resonant scattering of outer zone relativistic electrons by multiband EMIC waves and resultant electron loss time scales

et al. 2015

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To improve our understanding of the role of electromagnetic ion cyclotron (EMIC) waves in radiation belt electron dynamics, we perform a comprehensive analysis of EMIC wave‐induced resonant scattering of outer zone relativistic (>0.5 MeV) electrons and resultant electron loss time scales with respect to EMIC wave band, L shell, and wave normal angle model. The results demonstrate that while H+‐band EMIC waves dominate the scattering losses of ~1–4 MeV outer zone relativistic electrons, it is He+‐band and O+‐band waves that prevail over the pitch angle diffusion of ultrarelativistic electrons at higher energies. Given the wave amplitude, EMIC waves at higher L shells tend to resonantly interact with a larger population of outer zone relativistic electrons and drive their pitch angle scattering more efficiently. Obliquity of EMIC waves can reduce the efficiency of wave‐induced relativistic electron pitch angle scattering. Compared to the frequently adopted parallel or quasi‐parallel model, use of the latitudinally varying wave normal angle model produces the largest decrease in H+‐band EMIC wave scattering rates at pitch angles < ~40° for electrons > ~5 MeV. At a representative nominal amplitude of 1 nT, EMIC wave scattering produces the equilibrium state (i.e., the lowest normal mode under which electrons at the same energy but different pitch angles decay exponentially on the same time scale) of outer belt relativistic electrons within several to tens of minutes and the following exponential decay extending to higher pitch angles on time scales from <1 min to ~1 h. The electron loss cone can be either empty as a result of the weak diffusion or heavily/fully filled due to approaching the strong diffusion limit, while the trapped electron population at high pitch angles close to 90° remains intact because of no resonant scattering. In this manner, EMIC wave scattering has the potential to deepen the anisotropic distribution of outer zone relativistic electrons by reshaping their pitch angle profiles to “top‐hat.” Overall, H+‐band and He+‐band EMIC waves are most efficient in producing the pitch angle scattering loss of relativistic electrons at ~1–2 MeV. In contrast, the presence of O+‐band EMIC waves, while at a smaller occurrence rate, can dominate the scattering loss of 5–10 MeV electrons in the entire region of the outer zone, which should be considered in future modeling of the outer zone relativistic electron dynamics.

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An empirical plasmasphere and trough density model: CRRES observations

Abstract: Abstract. Combined Release and Radiation Effects

Cited by 439 publications

References 11 publications

The local-time variation of the quiet plasmasphere: geosynchronous observations and kinetic theory

The local-time variation of the quiet plasmasphere: geosynchronous observations and kinetic theory

Transport and loss of the inner plasma sheet electrons: THEMIS observations

Resonant scattering of outer zone relativistic electrons by multiband EMIC waves and resultant electron loss time scales

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