A quiescent state of 3 to 8 MeV radiation belt electrons

Selesnick, R. S.; Blake, J. B.; Kolasinski, W. A.; Fritz, T. A.

doi:10.1029/97gl51407

Cited by 55 publications

(72 citation statements)

References 6 publications

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“…A dipole magnetic field model was assumed for this relatively quiet interval. Overall, the radial diffusion calculation does well in accounting for the four orders of magnitude decrease in PSD over the 2-month interval following the March 24 injection, as have similar calculations over an extended quiet interval (Selesnick et al, 1997).…”

Section: Article In Pressmentioning

confidence: 83%

Relationship of the Van Allen radiation belts to solar wind drivers

Hudson

Kress

Mueller

et al. 2008

Journal of Atmospheric and Solar-Terrestrial Physics

121

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Section: Article In Pressmentioning

confidence: 83%

Relationship of the Van Allen radiation belts to solar wind drivers

Hudson

Kress

Mueller

et al. 2008

Journal of Atmospheric and Solar-Terrestrial Physics

121

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“…III.2) with magnetic spectral densities in a model magnetic field. Additionally efforts to model radial diffusion (e.g., Selesnick et al, 1997;Brautigam and Albert, 2000;Li et al, 2001) can lead to average estimates of the diffusion coefficient and consequent particle transport times. From modelling diffusion for all of 1998, Barker et al (2005) characterised the electron lifetime as a function of L-shell as τ = 3(6/L) 5.3 days.…”

Section: Radial Diffusionmentioning

confidence: 99%

Characterising electron butterfly pitch angle distributions in the magnetosphere through observations and simulations

Klida

Fritz

2013

Ann. Geophys.

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The Imaging Electron Spectrometer (IES) on the Polar satellite has measured the average characteristics of the equatorial electron pitch angle distributions (PADs) in the midnight sector as a function of radial distance out to the 9 RE apogee of the Polar satellite. Depressions in the observed fluxes of electrons occur with pitch angles around 90° in the equatorial zone, while the more field-aligned electrons remain largely unchanged. The orbital precessions of the satellite have allowed much of the inner equatorial magnetosphere to be observed. Statistically, butterfly PADs with different shapes are observed selectively in different regions, which can provide insight to their source and possible history. Electron paths of varied pitch angles were modelled using Runge-Kutta approximations of the Lorentz force in a Tsyganenko (T96) simulated magnetosphere. The resulting drift paths suggest that the process of magnetopause shadowing plays a significant role in the loss of these electrons. Case studies of the drifting patterns of electrons with varied pitch angles were simulated from Polar's orbit when a butterfly PAD was observed on 3 October 2002 at an altitude near 9 RE and on 12 September 2000 at an altitude near 6 RE. These two locations represent regions on each side of the boundary of stable trapping. The modelling effort strongly suggests that magnetopause shadowing does play a significant role in the loss of equatorially drifting electrons from the outer regions of the inner magnetosphere

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“…Radial diffusion, which occurs over a time scale of days, energizes electrons by bringing them inward from larger L shells [e.g., Schulz and Lanzerotti, 1974;Selesnick et al, 1997;Li and Temerin, 2001]. Processes that are m (magnetic moment)-breaking, such as local heating, have also been explored, for example the in situ heating of electrons by VLF waves on the same L shell [e.g., Temerin et al, 1994;Summers et al, 1998;Horne and Thorne, 1998;Meredith et al, 2001Meredith et al, , 2002Albert, 2002].…”

Section: Introductionmentioning

confidence: 99%

Parametric study of shock‐induced transport and energization of relativistic electrons in the magnetosphere

Gannon¹,

Li²,

Temerin³

2005

J. Geophys. Res.

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[1] The sudden appearance of a new radiation belt consisting of electrons with energies greater than 13 MeV near 2.5 Earth radii (R E ), was observed by CRRES (Combined Radiation and Release Experiment Satellite) on 24 March 1991. Li et al. (1993) showed that the cause was an electromagnetic pulse within the Earth's magnetosphere caused by an unusually strong, fast shock in the solar wind. Sudden shock-induced injections of electrons with energies above 10 MeV to equatorial distances within 2.5 R E are extremely rare because of the intensity of the shock required. In the current study, the propagation velocity parameter and electric field amplitude of pulses within the magnetosphere in the Li et al. model were varied from 750 to 2500 km/s and 70 to 400 mV/m, respectively. It was found that a stronger electric field shifted the peak of the resultant relativistic electron population toward the Earth. Doubling the electric field amplitude from 120 to 240 mV/m moved the peak of the injected electrons with energies above 13 MeV from 2.8 to 2.4 R E . However, as the electric field pulse becomes even larger, the increase in response diminishes. This asympotic behavior shows that it is extremely difficult to produce energetic electron injections inside two Earth radii. The nominal propagation velocity (velocity parameter) is compared to the radial propagation velocities that would have been measured under this model and others and compared to observation. It is found that although the model radial velocity is smaller than the velocity parameter and decreasing with radial distance, it is faster than MHD results and observations. Decreasing the nominal propagation velocity of the pulse within the magnetosphere from 2500 km/s to 1400 km/s also moved the peak of the injected electrons with energies above 13 MeV slightly closer to the Earth. However, at velocities smaller than approximately 1200 km/s the number of electrons injected within 2.5 Earth radii with energies above 13 MeV greatly decreased. Halving the velocity from 2000 to 1000 km/s shifted the peak of electrons with energy greater than 13 MeV from L = 2.6 to L = 2.4 but produced a count rate reduced by a factor of more than 250, resulting in no significant new radiation belt. These results show that the typical large electromagnetic impulses caused by interplanetary shocks, with amplitudes of the order of 10 mV/m, are more than an order of magnitude too small to produce any significant new radiation belts within 2.5 Earth radii with energies of the order of 10 MeV. Contributing to the difficulty in producing such a new belt is the need for an already relativistic electron population with adequate flux beyond geosynchronous orbit. These results thus also help explain the rarity of events such as the 24 March 1991 injection.Citation: Gannon, J. L., X. Li, and M. Temerin (2005), Parametric study of shock-induced transport and energization of relativistic electrons in the magnetosphere,

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A quiescent state of 3 to 8 MeV radiation belt electrons

Cited by 55 publications

References 6 publications

Relationship of the Van Allen radiation belts to solar wind drivers

Relationship of the Van Allen radiation belts to solar wind drivers

Characterising electron butterfly pitch angle distributions in the magnetosphere through observations and simulations

Parametric study of shock‐induced transport and energization of relativistic electrons in the magnetosphere

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