Geospace effects of high-speed solar wind streams

Morley, S.

doi:10.1098/rspa.2010.0371

Cited by 2 publications

(1 citation statement)

References 10 publications

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“…The response of the outer electron radiation belt to high‐speed‐stream‐driven storms has been extensively studied in recent years [cf. Tsurutani et al , 2006; Borovsky and Denton , 2006; Denton et al , 2008, 2009; Kavanagh and Denton , 2007; McPherron et al , 2009; Morley , 2010]. During high‐speed‐stream‐driven storms the outer electron radiation belt undergoes a characteristic pattern of evolution involving the following four phases.…”

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confidence: 99%

Evolution of the magnetotail energetic-electron population during high-speed-stream-driven storms: Evidence for the leakage of the outer electron radiation belt into the Earth's magnetotail

Borovsky

Denton

2011

J. Geophys. Res.

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[1] For 15 high-speed-stream-driven geomagnetic activations (weak storms) in [2006][2007], the temporal behaviors of the outer electron radiation belt at geosynchronous orbit and the energetic-electron population of the magnetotail are compared via superposed-epoch averaging of data. The magnetotail measurements are obtained by using GPS-orbit measurements that magnetically map out into the magnetotail. Four temporal phases of high-speed-stream-driven storms are studied: (1) the pre-storm density decay of the electron-radiation belt, (2) the electron-radiation-belt density dropout near the time of storm onset, (3) the rapid density recovery a few hours after dropout, and (4) the heating of the electron radiation belt during the high-speed-stream-driven geomagnetic activity. In all four phases the behaviors of the outer electron radiation belt and of the energetic-electron population in the magnetotail are the same and simultaneous. The physical explanations for the behavior in phase 1 (decay), phase 2 (dropout), and phase 4 (heating) lie in the dipolar regions of the magnetosphere: hence for those three phases it is concluded that the temporal behavior of the energetic-electron population in the magnetotail mimics the behavior of the outer electron radiation belt. Behavior attributable to physical processes in the dipole is seen in the magnetotail energetic-electron population: this implies that the origin of the energetic-electron population of the magnetotail is "leakage" or "outward evaporation" from the outer electron radiation belt in the dipolar magnetosphere.Citation: Borovsky, J. E., and M. H. Denton (2011), Evolution of the magnetotail energetic-electron population during high-speed-stream-driven storms: Evidence for the leakage of the outer electron radiation belt into the Earth's magnetotail,

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Section: Introductionmentioning

confidence: 99%

Evolution of the magnetotail energetic-electron population during high-speed-stream-driven storms: Evidence for the leakage of the outer electron radiation belt into the Earth's magnetotail

Borovsky

Denton

2011

J. Geophys. Res.

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On the relationship between relativistic electron flux and solar wind velocity: Paulikas and Blake revisited

et al. 2011

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[1] Thirty years ago Paulikas and Blake (1979) showed a remarkable correlation between geosynchronous relativistic electron fluxes and solar wind speed (Vsw). This seminal result has been a foundation of radiation belt studies, space weather forecasting, and current understanding of solar wind radiation belt coupling. We have repeated their analysis with a considerably longer-running data set from the Los Alamos National Laboratory energetic particle instruments with several surprising results. Rather than the roughly linear correlation between Vsw and log (flux), our results show a triangle-shaped distribution in which fluxes have a distinct velocity-dependent lower limit but a velocity-independent upper limit. The highest-electron fluxes can occur for any value of Vsw with no indication of a Vsw threshold. We also find a distinct solar cycle dependence with the triangle-shaped distribution evident in 2 declining phase years dominated by high-speed streams but essentially no correlation in 2 solar maximum years. For time periods that do show a triangle-shaped distribution we consider whether it can be explained by scatter due to other parameters. We examine the role of time dependence and time lag in producing the observed distribution. We also look at the same statistical relationship but at energies 1 MeV. We conclude that the relationship between radiation belt electron fluxes and solar wind velocity is substantially more complex than suggested by previous statistical studies. We find that there are important ways in which the "conventional wisdom" stating that high-velocity wind drives high-MeV electron fluxes is, in general, either misleading or unsupported.

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Geospace effects of high-speed solar wind streams

Cited by 2 publications

References 10 publications

Evolution of the magnetotail energetic-electron population during high-speed-stream-driven storms: Evidence for the leakage of the outer electron radiation belt into the Earth's magnetotail

Evolution of the magnetotail energetic-electron population during high-speed-stream-driven storms: Evidence for the leakage of the outer electron radiation belt into the Earth's magnetotail

On the relationship between relativistic electron flux and solar wind velocity: Paulikas and Blake revisited

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