The Fly’s Eye Energetic Particle Spectrometer (FEEPS) Sensors for the Magnetospheric Multiscale (MMS) Mission

Blake, J. B.; Mauk, B. H.; Baker, D. N.; Carranza, P.; Clemmons, J. H.; Craft, James A.; Crain, William R.; Crew, A. B.; Dotan, Y.; Fennell, J. F.; Friedel, R. H.; Friesen, L. M.; Fuentes, F.; Galvan, R.; Ibscher, C.; Jaynes, Allison; Katz, N.; Lalić, M.V.; Lin, Albert Y.; Mabry, D. J.; Nguyen, Trinh T.; Pancratz, C.; Redding, M.; Reeves, G. D.; Smith, S. S.; Spence, H. E.; Westlake, J. H.

doi:10.1007/978-94-024-0861-4_11

Cited by 46 publications

(56 citation statements)

References 5 publications

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“…Figures c–g show changes of the energy and PAD of electrons for the selected energy ranges. Pitch angle spectra are shown for energy range of 119 keV–129 keV (Figure d) and 65 keV–75 keV (Figure e), obtained from the energetic particle detector/fly's eye energetic particle spectrometer instrument (Blake et al, ) aboard MMS 2 depicting the nonthermal electron pitch angle signatures and for 2 keV–30 keV (Figure f) and 200 eV–2 keV (Figure g) obtained from FPI measurement aboard MMS 3 depicting the thermal part of the electron signatures.…”

Section: Fac Layers and Characteristics Of Electronsmentioning

confidence: 99%

Multiscale Currents Observed by MMS in the Flow Braking Region

et al. 2018

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We present characteristics of current layers in the off‐equatorial near‐Earth plasma sheet boundary observed with high time‐resolution measurements from the Magnetospheric Multiscale mission during an intense substorm associated with multiple dipolarizations. The four Magnetospheric Multiscale spacecraft, separated by distances of about 50 km, were located in the southern hemisphere in the dusk portion of a substorm current wedge. They observed fast flow disturbances (up to about 500 km/s), most intense in the dawn‐dusk direction. Field‐aligned currents were observed initially within the expanding plasma sheet, where the flow and field disturbances showed the distinct pattern expected in the braking region of localized flows. Subsequently, intense thin field‐aligned current layers were detected at the inner boundary of equatorward moving flux tubes together with Earthward streaming hot ions. Intense Hall current layers were found adjacent to the field‐aligned currents. In particular, we found a Hall current structure in the vicinity of the Earthward streaming ion jet that consisted of mixed ion components, that is, hot unmagnetized ions, cold E × B drifting ions, and magnetized electrons. Our observations show that both the near‐Earth plasma jet diversion and the thin Hall current layers formed around the reconnection jet boundary are the sites where diversion of the perpendicular currents take place that contribute to the observed field‐aligned current pattern as predicted by simulations of reconnection jets. Hence, multiscale structure of flow braking is preserved in the field‐aligned currents in the off‐equatorial plasma sheet and is also translated to ionosphere to become a part of the substorm field‐aligned current system.

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Section: Fac Layers and Characteristics Of Electronsmentioning

confidence: 99%

Multiscale Currents Observed by MMS in the Flow Braking Region

et al. 2018

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“…Part of the Energetic Particle Detector (EPD) investigation on MMS, EIS measures energetic ion energy, angle, and compositional distributions from ∼20 keV (protons), ∼60 keV (helium), and ∼130 keV (oxygen) up to ∼1 MeV [ Mauk et al , ]. EIS also measures energetic electrons from 25 to 600 keV in support of the faster and more sensitive electron measurements made by the EPD Fly's Eye Energetic Particle Spectrometer (FEEPS) sensors [ Blake et al , ]. In the survey mode utilized here, EIS samples at 1/8 the spacecraft spin rate (∼2.5 s).…”

Section: Observations and Analysismentioning

confidence: 99%

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

Cohen

Mauk

Anderson

et al. 2016

Geophysical Research Letters

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Energetic (greater than tens of keV) magnetospheric particle escape into the magnetosheath occurs commonly, irrespective of conditions that engender reconnection and boundary‐normal magnetic fields. A signature observed by the Magnetospheric Multiscale (MMS) mission, simultaneous monohemispheric streaming of multiple species (electrons, H+, Hen+), is reported here as unexpectedly common in the dayside, dusk quadrant of the magnetosheath even though that region is thought to be drift‐shadowed from energetic electrons. This signature is sometimes part of a pitch angle distribution evolving from symmetric in the magnetosphere, to asymmetric approaching the magnetopause, to monohemispheric streaming in the magnetosheath. While monohemispheric streaming in the magnetosheath may be possible without a boundary‐normal magnetic field, the additional pitch angle depletion, particularly of electrons, on the magnetospheric side requires one. Observations of this signature in the dayside dusk sector imply that the static picture of magnetospheric drift‐shadowing is inappropriate for energetic particle dynamics in the outer magnetosphere.

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“…Examples from four FEEPS eyes are shown in Figure a. The vertical purple lines across the panels show that the different eyes observe the electrons at different spin phase consistent with their field‐of‐view azimuthal position [ Blake et al ., , Figure 2]. Eyes ID‐3 and ID‐11 view north of the spin plane, while eyes ID‐4 and ID‐12 view south of the spin plane.…”

Section: Observationsmentioning

confidence: 99%

Microinjections observed by MMS FEEPS in the dusk to midnight region

Fennell

Turner

Lemon

et al. 2016

Geophysical Research Letters

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Energetic electron injections are commonly observed in the premidnight to dawn regions in association with substorms. However, successive electron injections are generally separated in time by hours and are rarer in the dusk region of the inner magnetosphere. Early MMS energetic electron data taken in the dusk to premidnight regions above ~9 RE show many clusters of electron injections. These injections of 50–400 keV electrons have energy dispersion signatures indicating that they gradient and curvature drifted from earlier local times. We focus on burst rate data starting near 21:00 UT on 6 August 2015. A cluster of ~40 electron injections occurred in the following 4 h interval. The highest‐resolution data showed that the electrons in the injections were trapped and had bidirectional field‐aligned angular distributions. These injection clusters are a new phenomenon in this region of the magnetosphere.

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The Fly’s Eye Energetic Particle Spectrometer (FEEPS) Sensors for the Magnetospheric Multiscale (MMS) Mission

Cited by 46 publications

References 5 publications

Multiscale Currents Observed by MMS in the Flow Braking Region

Multiscale Currents Observed by MMS in the Flow Braking Region

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

Microinjections observed by MMS FEEPS in the dusk to midnight region

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