Dayside response of the magnetosphere to a small shock compression: Van Allen Probes, Magnetospheric MultiScale, and GOES‐13

Cattell, C. A.; Breneman, A. W.; Colpitts, C. A.; Dombeck, J.; Thaller, S. A.; Tian, S.; Wygant, J. R.; Fennell, J. F.; Hudson, M. K.; Ergun, R. E.; Russell, C. T.; Torbert, R. B.; Lindqvist, Per‐Arne; Burch, J. L.

doi:10.1002/2017gl074895

Cited by 14 publications

(24 citation statements)

References 57 publications

(74 reference statements)

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“…The statistics in Liu et al [2017] also showed that the dynamic pressures of the IP shocks associated with dropout echo events are usually modest. As well, the radial propagation speed of the pulse v 0 = 1,000 km/s and the averaged azimuthal propagation speed of the pulse 691 km/s at L = 6.6 in our study are consistent with the propagation velocity ranged from about 600 to 1,300 km/s obtained in previous observations (Cattell et al, 2017;Foster et al, 2015;Schmidt & Pedersen, 1988;Takahashi et al, 2017;Zong et al, 2009). As well, the radial propagation speed of the pulse v 0 = 1,000 km/s and the averaged azimuthal propagation speed of the pulse 691 km/s at L = 6.6 in our study are consistent with the propagation velocity ranged from about 600 to 1,300 km/s obtained in previous observations (Cattell et al, 2017;Foster et al, 2015;Schmidt & Pedersen, 1988;Takahashi et al, 2017;Zong et al, 2009).…”

Section: The Shock-induced Magnetosonic Pulsesupporting

confidence: 93%

“…In fact, various studies have indicated that the response of magnetosphere to an IP shock could be characterized by the propagating magnetosonic pulse. The observations on the profile and propagation of the sudden impulse induced by IP shocks also confirm the picture of the propagating magnetosonic pulse (e.g., Cattell et al, 2017;Schmidt & Pedersen, 1988;Shinbori et al, 2004;Takahashi et al, 2017;Zhang et al, 2018). Further, global magnetohydrodynamics (MHD) simulations showed the propagation of the shock-induced magnetosonic pulse through the whole magnetosphere (e.g., Guo et al, 2005;Ridley et al, 2006;Samsonov et al, 2007).…”

Section: The Shock-induced Magnetosonic Pulsesupporting

confidence: 66%

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Understanding Electron Dropout Echoes Induced by Interplanetary Shocks: Test Particle Simulations

et al. 2019

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Recently, interplanetary shocks have been reported to cause “electron dropout echoes” in the outer radiation belt, which is manifested as repeated dropout and recovery signals in electron fluxes. Both previous case and statistical studies have shown that electron dropout echoes are mostly found for high‐energy (>300 keV) electrons, and the initial dropout region is mainly located at the dusk magnetosphere, regardless of shock parameters such as shock normal. To understand these properties, we model the electron dropout echoes at geosynchronous orbit by tracing electrons in the analytic field model of the shock‐induced propagating pulse. It is shown that the characteristics of shock‐induced electron dropout echo events including energy dependence and localization are well reproduced by our model. By analyzing the trajectories of typical electrons, we find that electrons are inward transported and accelerated through “drift‐resonance‐like” interactions with the magnetosonic pulse. Two causes of the dawn‐dusk asymmetric response are presented: (1) the difference between the interaction time of electrons with the magnetosonic pulse and (2) the opposite radial ∇B drift of the electrons at dawnside and duskside. Further, we calculate the contributions to electron dynamics and phase space density variations from three terms: E×B drift, radial ∇B drift, and gyrobetatron acceleration. The details of electron flux variations could vary with the form of the shock‐induced pulse and the initial electron distribution, thus be different from our results; however, the basic ingredients of the electron interaction with the pulse could provide a general frame for understanding and evaluating electron flux responses.

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Section: The Shock-induced Magnetosonic Pulsesupporting

confidence: 93%

Section: The Shock-induced Magnetosonic Pulsesupporting

confidence: 66%

Understanding Electron Dropout Echoes Induced by Interplanetary Shocks: Test Particle Simulations

et al. 2019

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“…This effect has been used to explain the dispersionless injections during substorms with a decelerating impulse (e.g., Li et al, 1998;Sarris et al, 2002). However, this effect could be negligible for IPS-induced electric field impulses, as the V E × B caused by the impulsive electric field, calculated above to be below 100 km/s, is much smaller than the propagation speed of the impulse, which is about 600 to 1,100 km/s corresponding to local fast magnetosonic wave speed estimates (e.g., Cattell et al, 2017;Foster et al, 2015;Schmidt & Pedersen, 1987;Takahashi et al, 2017). The second mechanism involves electrons with the right energy that can follow a propagating impulse while drifting azimuthally.…”

Section: 1029/2018gl078809mentioning

confidence: 98%

Observations of Impulsive Electric Fields Induced by Interplanetary Shock

Zhang

Liu

et al. 2018

Geophysical Research Letters

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We investigate the characteristics of impulsive electric fields in the Earth's magnetosphere, as measured by the Van Allen Probes, in association with interplanetary shocks, as measured by Advanced Composition Explorer and Wind spacecraft in the solar wind from January 2013 to July 2016. It is shown that electric field impulses are mainly induced by global compressions by the shocks, mostly in the azimuthal direction, and the amplitudes of the initial electric field impulses are positively correlated with the rate of increase of the dynamic pressure across the shock in the dayside. It is also shown that the temporal profile of the impulse is related to the temporal profile of the solar wind dynamic pressure, Pd. It is suggested that during the first period of the impulse, the evolution of the electric field is directly controlled by external solar wind forcing, and thus, finite rates of change of Pd should be considered in the study of the interactions between solar wind and magnetosphere. The implications of shock‐induced impulsive electric fields on the acceleration and transport of radiation belt electrons are also discussed.

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“…Cattell et al () documented the impact of the modest interplanetary shock that was observed upstream of Earth by ACE at 1231 UT and by Wind at 1241 UT. The shock compressed the dayside magnetopause to inside 8 R E .…”

Section: Satellite Observationsmentioning

confidence: 99%

MMS, Van Allen Probes, GOES 13, and Ground‐Based Magnetometer Observations of EMIC Wave Events Before, During, and After a Modest Interplanetary Shock

et al. 2018

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The stimulation of electromagnetic ion cyclotron (EMIC) waves by a magnetospheric compression is perhaps the closest thing to a controlled experiment that is currently possible in magnetospheric physics, in that one prominent factor that can increase wave growth acts at a well-defined time. We present a detailed analysis of EMIC waves observed in the outer dayside magnetosphere by the four Magnetosphere Multiscale (MMS) spacecraft, Van Allen Probe A, and GOES 13 and by four very high latitude ground magnetometer stations in the western hemisphere before, during, and after a modest interplanetary shock on 14 December 2015. Analysis shows several features consistent with current theory, as well as some unexpected features. During the most intense MMS wave burst, which began~1 min after the end of a brief magnetosheath incursion, independent transverse EMIC waves with orthogonal linear polarizations appeared simultaneously at all four spacecraft. He ++ band EMIC waves were observed by MMS inside the magnetosphere, whereas almost all previous studies of He ++ band EMIC waves observed them only in the magnetosheath and magnetopause boundary layers. Transverse EMIC waves also appeared at Van Allen Probe A and GOES 13 very near the times when the magnetic field compression reached their locations, indicating that the compression lowered the instability threshold to allow for EMIC wave generation throughout the outer dayside magnetosphere. The timing of the EMIC waves at both MMS and Van Allen Probe A was consistent with theoretical expectations for EMIC instabilities based on characteristics of the proton distributions observed by instruments on these spacecraft., a cyclotron resonance can occur when the Doppler-shifted wave frequency ω equals the cyclotron frequency ω p of the protons. This resonance causes wave growth and pitch angle scattering leading to the precipitation of a fraction of the protons into the ionosphere.

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Dayside response of the magnetosphere to a small shock compression: Van Allen Probes, Magnetospheric MultiScale, and GOES‐13

Cited by 14 publications

References 57 publications

Understanding Electron Dropout Echoes Induced by Interplanetary Shocks: Test Particle Simulations

Understanding Electron Dropout Echoes Induced by Interplanetary Shocks: Test Particle Simulations

Observations of Impulsive Electric Fields Induced by Interplanetary Shock

MMS, Van Allen Probes, GOES 13, and Ground‐Based Magnetometer Observations of EMIC Wave Events Before, During, and After a Modest Interplanetary Shock

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