Observations of energetic particle escape at the magnetopause: Early results from the MMS Energetic Ion Spectrometer (EIS)

Cohen, I. J.; Mauk, B. H.; Anderson, B. J.; Westlake, J. H.; Sibeck, D. G.; Giles, B. L.; Pollock, C. J.; Turner, D. L.; Fennell, J. F.; Blake, J. B.; Clemmons, J. H.; Jaynes, A. N.; Baker, D. N.; Craft, James A.; Spence, H. E.; Niehof, J. T.; Reeves, G. D.; Torbert, R. B.; Russell, C. T.; Strangeway, R. J.; Magnes, W.; Trattner, K. J.; Fuselier, S. A.; Burch, J. L.

doi:10.1002/2016gl068689

Cited by 25 publications

(48 citation statements)

References 41 publications

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“…Figure illustrates the various measurement capabilities of the Puck with data from the MMS‐EIS [ Cohen et al, ]. Figure c shows the electron measurements from the large pixel electron SSD.…”

Section: In‐flight Performancementioning

confidence: 99%

“…Furthermore, Ukhorskiy et al [] used RBSPICE measurements to show that energetic electrons (<1 MeV) across the entire inner radiation belt (<3 R E ) are organized in regular patterns, named “zebra stripes,” which are thought to be the result of diurnal oscillations of the inductive electric field induced by Earth's rotation. Meanwhile, early measurements from EIS demonstrate an unprecedented level of energetic particle dynamics at the dayside terrestrial magnetopause [e.g., Anderson et al ., ; Cohen et al, ]. Finally, the Juno‐JEDI instrument is expected to unveil new clues about auroral acceleration and magnetosphere‐ionosphere coupling at Jupiter.…”

Section: In‐flight Performancementioning

confidence: 99%

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The “Puck” energetic charged particle detector: Design, heritage, and advancements

et al. 2016

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Energetic charged particle detectors characterize a portion of the plasma distribution function that plays critical roles in some physical processes, from carrying the currents in planetary ring currents to weathering the surfaces of planetary objects. For several low‐resource missions in the past, the need was recognized for a low‐resource but highly capable, mass‐species‐discriminating energetic particle sensor that could also obtain angular distributions without motors or mechanical articulation. This need led to the development of a compact Energetic Particle Detector (EPD), known as the “Puck” EPD (short for hockey puck), that is capable of determining the flux, angular distribution, and composition of incident ions between an energy range of ~10 keV to several MeV. This sensor makes simultaneous angular measurements of electron fluxes from the tens of keV to about 1 MeV. The same measurements can be extended down to approximately 1 keV/nucleon, with some composition ambiguity. These sensors have a proven flight heritage record that includes missions such as MErcury Surface, Space ENvironment, GEochemistry, and Ranging and New Horizons, with multiple sensors on each of Juno, Van Allen Probes, and Magnetospheric Multiscale. In this review paper we discuss the Puck EPD design, its heritage, unexpected results from these past missions and future advancements. We also discuss high‐voltage anomalies that are thought to be associated with the use of curved foils, which is a new foil manufacturing processes utilized on recent Puck EPD designs. Finally, we discuss the important role Puck EPDs can potentially play in upcoming missions.

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Section: In‐flight Performancementioning

confidence: 99%

Section: In‐flight Performancementioning

confidence: 99%

The “Puck” energetic charged particle detector: Design, heritage, and advancements

et al. 2016

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“…The model emulates the measured configuration of the fields (electric and magnetic) in the magnetosphere and magnetosheath and the rotational structure of the magnetic field within the 400 km thick model magnetopause used here [cf. Cohen et al, 2016] and explicitly solves the particle trajectories. For this run, the magnetopause contains a boundary normal magnetic field that is 5% of the nominal magnetosheath magnetic field strength.…”

Section: 1002/2016gl070189mentioning

confidence: 99%

The permeability of the magnetopause to a multispecies substorm injection of energetic particles

Westlake

Cohen

Mauk

et al. 2016

Geophysical Research Letters

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Leakage of ions from the magnetosphere into the magnetosheath remains an important topic in understanding the plasma physics of Earth's magnetopause and the interaction of the solar wind with the magnetosphere. Here using sophisticated instrumentation from two spacecraft (Radiation Belt Storm Probes Ion Composition Experiment on the Van Allen Probes and Energetic Ion Spectrometer on the Magnetospheric Multiscale) spaced uniquely near and outside the dayside magnetopause, we are able to determine the escape mechanisms for large gyroradii oxygen ions and much smaller gyroradii hydrogen and helium ions. The oxygen ions are entrained on the magnetosphere boundary, while the hydrogen and helium ions appear to escape along reconnected field lines. These results have important implications for not only Earth's magnetosphere but also other solar system magnetospheres.

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“…In the second scenario, no energization and acceleration need to take place near the magnetopause directly associated with the KHWs and FTEs. The magnetopause boundary is already populated with energetic electrons from within the inner magnetosphere (Cohen et al, ; Mauk, Cohen, et al, ) and could represent a preexisting, drifting population that the boundary motions simply modulate. These electrons are those that have leaked out across the boundary and then become trapped in the boundary layer (Mauk & Meng, ).…”

Section: Summary and Discussionmentioning

confidence: 99%

MMS/FEEPS Observations of Electron Microinjections Due to Kelvin‐Helmholtz Waves and Flux Transfer Events: A Case Study

et al. 2018

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The Energetic Particle Detector (EPD) suite onboard the Magnetospheric Multiscale (MMS) spacecraft observes dispersive and repetitive fluxes of high‐energy (50–400 keV) electrons within the Pc5 frequency band (2–8 MHz) in the dusk to midnight region of Earth's magnetotail. These microinjections are a new phenomenon in this region of the magnetosphere, presently poorly understood, but clearly a new signature that remotely senses large‐scale magnetospheric boundary dynamics. It is therefore important to understand their properties and driver mechanisms. Here we have combined global magnetohydrodynamic simulations and particle tracing results with the MMS EPD Fly's Eye Energetic Particle Spectrometer (FEEPS) observations to investigate possible origins and source regions of the electron microinjections. Our simulation results suggest that the electron microinjections, observed in the dusk to premidnight sector, are associated with Kelvin‐Helmholtz waves (KHWs) and flux transfer events (FTEs). Energetic electrons launched from a limited range of locations near the postnoon dusk magnetopause and at times when KHWs and FTEs pass by that region have drift paths that connect with MMS and thus create time‐dependent microinjection electron signatures. Test‐particle tracing results in the magnetohydrodynamic fields also support the field‐aligned nature of electron microinjections observed by MMS. Though identifying the mechanism by which KHWs and FTEs might periodically inject electrons is beyond the scope of this work, our study does identify these duskside magnetopause boundary phenomena as likely agents of microinjection origins.

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Observations of energetic particle escape at the magnetopause: Early results from the MMS Energetic Ion Spectrometer (EIS)

Cited by 25 publications

References 41 publications

The “Puck” energetic charged particle detector: Design, heritage, and advancements

The “Puck” energetic charged particle detector: Design, heritage, and advancements

The permeability of the magnetopause to a multispecies substorm injection of energetic particles

MMS/FEEPS Observations of Electron Microinjections Due to Kelvin‐Helmholtz Waves and Flux Transfer Events: A Case Study

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