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Journal ArticleDOI

The Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) on RBSP

TL;DR: The Electric and Magnetic Field Instrument and Integrated Science (EMFISIS) investigation on the NASA Radiation Belt Storm Probes (now named the Van Allen Probes) mission provides key wave and very low frequency magnetic field measurements to understand radiation belt acceleration, loss, and transport.
Abstract: The Electric and Magnetic Field Instrument and Integrated Science (EMFISIS) investigation on the NASA Radiation Belt Storm Probes (now named the Van Allen Probes) mission provides key wave and very low frequency magnetic field measurements to understand radiation belt acceleration, loss, and transport. The key science objectives and the contribution that EMFISIS makes to providing measurements as well as theory and modeling are described. The key components of the instruments suite, both electronics and sensors, including key functional parameters, calibration, and performance, demonstrate that EMFISIS provides the needed measurements for the science of the RBSP mission. The EMFISIS operational modes and data products, along with online availability and data tools provide the radiation belt science community with one the most complete sets of data ever collected.

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Citations
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Journal ArticleDOI
TL;DR: The NASA Radiation Belt Storm Probes (RBSP) mission as discussed by the authors uses two spacecraft making in situ measurements for at least 2 years in nearly the same highly elliptical, low inclination orbits (1.1×5.8 RE, 10∘).
Abstract: The NASA Radiation Belt Storm Probes (RBSP) mission addresses how populations of high energy charged particles are created, vary, and evolve in space environments, and specifically within Earth’s magnetically trapped radiation belts. RBSP, with a nominal launch date of August 2012, comprises two spacecraft making in situ measurements for at least 2 years in nearly the same highly elliptical, low inclination orbits (1.1×5.8 RE, 10∘). The orbits are slightly different so that 1 spacecraft laps the other spacecraft about every 2.5 months, allowing separation of spatial from temporal effects over spatial scales ranging from ∼0.1 to 5 RE. The uniquely comprehensive suite of instruments, identical on the two spacecraft, measures all of the particle (electrons, ions, ion composition), fields (E and B), and wave distributions (d E and d B) that are needed to resolve the most critical science questions. Here we summarize the high level science objectives for the RBSP mission, provide historical background on studies of Earth and planetary radiation belts, present examples of the most compelling scientific mysteries of the radiation belts, present the mission design of the RBSP mission that targets these mysteries and objectives, present the observation and measurement requirements for the mission, and introduce the instrumentation that will deliver these measurements. This paper references and is followed by a number of companion papers that describe the details of the RBSP mission, spacecraft, and instruments.

1,004 citations

Journal ArticleDOI
19 Dec 2013-Nature
TL;DR: High-resolution electron observations obtained during the 9 October storm are reported and chorus scattering explains the temporal evolution of both the energy and angular distribution of the observed relativistic electron flux increase, and detailed modelling demonstrates the remarkable efficiency of wave acceleration in the Earth's outer radiation belt.
Abstract: Recent analysis of satellite data obtained during the 9 October 2012 geomagnetic storm identified the development of peaks in electron phase space density, which are compelling evidence for local electron acceleration in the heart of the outer radiation belt, but are inconsistent with acceleration by inward radial diffusive transport. However, the precise physical mechanism responsible for the acceleration on 9 October was not identified. Previous modelling has indicated that a magnetospheric electromagnetic emission known as chorus could be a potential candidate for local electron acceleration, but a definitive resolution of the importance of chorus for radiation-belt acceleration was not possible because of limitations in the energy range and resolution of previous electron observations and the lack of a dynamic global wave model. Here we report high-resolution electron observations obtained during the 9 October storm and demonstrate, using a two-dimensional simulation performed with a recently developed time-varying data-driven model, that chorus scattering explains the temporal evolution of both the energy and angular distribution of the observed relativistic electron flux increase. Our detailed modelling demonstrates the remarkable efficiency of wave acceleration in the Earth's outer radiation belt, and the results presented have potential application to Jupiter, Saturn and other magnetized astrophysical objects.

665 citations

Journal ArticleDOI
TL;DR: The Radiation Belt Storm Probes (RBSP)-Energetic Particle, Composition, and Thermal Plasma (ECT) suite contains an innovative complement of particle instruments to ensure the highest quality measurements ever made in the inner magnetosphere and radiation belts as mentioned in this paper.
Abstract: The Radiation Belt Storm Probes (RBSP)-Energetic Particle, Composition, and Thermal Plasma (ECT) suite contains an innovative complement of particle instruments to ensure the highest quality measurements ever made in the inner magnetosphere and radiation belts. The coordinated RBSP-ECT particle measurements, analyzed in combination with fields and waves observations and state-of-the-art theory and modeling, are necessary for understanding the acceleration, global distribution, and variability of radiation belt electrons and ions, key science objectives of NASA’s Living With a Star program and the Van Allen Probes mission. The RBSP-ECT suite consists of three highly-coordinated instruments: the Magnetic Electron Ion Spectrometer (MagEIS), the Helium Oxygen Proton Electron (HOPE) sensor, and the Relativistic Electron Proton Telescope (REPT). Collectively they cover, continuously, the full electron and ion spectra from one eV to 10’s of MeV with sufficient energy resolution, pitch angle coverage and resolution, and with composition measurements in the critical energy range up to 50 keV and also from a few to 50 MeV/nucleon. All three instruments are based on measurement techniques proven in the radiation belts. The instruments use those proven techniques along with innovative new designs, optimized for operation in the most extreme conditions in order to provide unambiguous separation of ions and electrons and clean energy responses even in the presence of extreme penetrating background environments. The design, fabrication and operation of ECT spaceflight instrumentation in the harsh radiation belt environment ensure that particle measurements have the fidelity needed for closure in answering key mission science questions. ECT instrument details are provided in companion papers in this same issue.

492 citations


Cites methods from "The Electric and Magnetic Field Ins..."

  • ...Higher quality magnetic field data (EMFISIS level 2) subsequently flows into the SDC when they become available....

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  • ...Using the DC magnetic field measurements from EMFISIS (Kletzing et al. 2013) with ECT particle fluxes we will achieve science closure by: (1) measuring the temporal evolution of phase space density gradients over a range of adiabatic invariants, (2) examining the evolution of the pitch angle…...

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  • ...Higher level analysis of the particle data requires knowledge of the magnetic field vector at each spacecraft and these data are obtained in a preliminary format directly from the EMFISIS Fields and Waves team SOC (quicklook product)....

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  • ...Using the DC magnetic field measurements from EMFISIS (Kletzing et al. 2013) with ECT particle fluxes we will achieve science closure by: (1) measuring the temporal evolution of phase space density gradients over a range of adiabatic invariants, (2) examining the evolution of the pitch angle distributions at different drift shells, (3) correlating with ULF field observations, and (4) looking for drift phase-bunching of electrons that resonate with ULF waves....

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Journal ArticleDOI
TL;DR: In this paper, the Van Allen Probes were used to measure three dimensional quasi-static and low frequency electric fields and waves associated with the acceleration of energetic charged particles in the inner magnetosphere of the Earth.
Abstract: The Electric Fields and Waves (EFW) Instruments on the two Radiation Belt Storm Probe (RBSP) spacecraft (recently renamed the Van Allen Probes) are designed to measure three dimensional quasi-static and low frequency electric fields and waves associated with the major mechanisms responsible for the acceleration of energetic charged particles in the inner magnetosphere of the Earth. For this measurement, the instrument uses two pairs of spherical double probe sensors at the ends of orthogonal centripetally deployed booms in the spin plane with tip-to-tip separations of 100 meters. The third component of the electric field is measured by two spherical sensors separated by ∼15 m, deployed at the ends of two stacer booms oppositely directed along the spin axis of the spacecraft. The instrument provides a continuous stream of measurements over the entire orbit of the low frequency electric field vector at 32 samples/s in a survey mode. This survey mode also includes measurements of spacecraft potential to provide information on thermal electron plasma variations and structure. Survey mode spectral information allows the continuous evaluation of the peak value and spectral power in electric, magnetic and density fluctuations from several Hz to 6.5 kHz. On-board cross-spectral data allows the calculation of field-aligned wave Poynting flux along the magnetic field. For higher frequency waveform information, two different programmable burst memories are used with nominal sampling rates of 512 samples/s and 16 k samples/s. The EFW burst modes provide targeted measurements over brief time intervals of 3-d electric fields, 3-d wave magnetic fields (from the EMFISIS magnetic search coil sensors), and spacecraft potential. In the burst modes all six sensor-spacecraft potential measurements are telemetered enabling interferometric timing of small-scale plasma structures. In the first burst mode, the instrument stores all or a substantial fraction of the high frequency measurements in a 32 gigabyte burst memory. The sub-intervals to be downloaded are uplinked by ground command after inspection of instrument survey data and other information available on the ground. The second burst mode involves autonomous storing and playback of data controlled by flight software algorithms, which assess the “highest quality” events on the basis of instrument measurements and information from other instruments available on orbit. The EFW instrument provides 3-d wave electric field signals with a frequency response up to 400 kHz to the EMFISIS instrument for analysis and telemetry (Kletzing et al. Space Sci. Rev. 2013).

479 citations


Cites methods from "The Electric and Magnetic Field Ins..."

  • ...The EFW instrument transfers three high frequency analog differential electric field signals to the EMFISIS instrument (Kletzing et al. 2013, this issue)....

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  • ...Search Coil Signals The three components of the wave magnetic field from the EMFISIS search coils (Kletzing et al. 2013) are provided to the EFW instrument via analog lines where they are digitized along with the electric field signals....

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  • ...6 presents a calibration of the spacecraft potential versus density as determined from measurements of the upper hybrid frequency by the EMFISIS instrument (Kletzing et al. 2013) over the density range from 1 to 10−3 during one orbit....

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  • ...The wave magnetic field is measured by the magnetic search coil sensor in the EMFISIS instrument (Kletzing et al. 2013) and provided to the EFW instrument via an analog interface....

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Journal ArticleDOI
TL;DR: The expected accuracy of ne and issues in the interpretation of the electrostatic wave spectrum are described and described.
Abstract: The twin Van Allen Probe spacecraft, launched in August 2012, carry identical scientific payloads. The Electric and Magnetic Field Instrument Suite and Integrated Science suite includes a plasma wave instrument (Waves) that measures three magnetic and three electric components of plasma waves in the frequency range of 10 Hz to 12 kHz using triaxial search coils and the Electric Fields and Waves triaxial electric field sensors. The Waves instrument also measures a single electric field component of waves in the frequency range of 10 to 500 kHz. A primary objective of the higher-frequency measurements is the determination of the electron density ne at the spacecraft, primarily inferred from the upper hybrid resonance frequency fuh. Considerable work has gone into developing a process and tools for identifying and digitizing the upper hybrid resonance frequency in order to infer the electron density as an essential parameter for interpreting not only the plasma wave data from the mission but also as input to various magnetospheric models. Good progress has been made in developing algorithms to identify fuh and create a data set of electron densities. However, it is often difficult to interpret the plasma wave spectra during active times to identify fuh and accurately determine ne. In some cases, there is no clear signature of the upper hybrid band, and the low-frequency cutoff of the continuum radiation is used. We describe the expected accuracy of ne and issues in the interpretation of the electrostatic wave spectrum.

428 citations

References
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Journal ArticleDOI
TL;DR: In this article, the authors present a computational scheme for compressible magnetohydrodynamics (MHD) based on the same elements that make up many modern compressible gas dynamics codes: high-resolution upwinding based on an approximate Riemann solver for MHD and limited reconstruction; an optimally smoothing multi-stage time-stepping scheme; and solution-adaptive refinement and coarsening.

1,412 citations


"The Electric and Magnetic Field Ins..." refers methods in this paper

  • ...…empirical electric fields (e.g., Weimer 2001) and boundary conditions or by those provided from a global magnetohydrodynamics (MHD) model, e.g. BATSRUS (Powell et al. 1999) selfconsistently coupled with an electric field model (RIM) (Ridley and Liemohn 2002) and driven by dynamic solar wind input....

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  • ...The RAM-SCB model can be driven either by empirical electric fields (e.g., Weimer 2001) and boundary conditions or by those provided from a global magnetohydrodynamics (MHD) model, e.g. BATSRUS (Powell et al. 1999) selfconsistently coupled with an electric field model (RIM) (Ridley and Liemohn 2002) and driven by dynamic solar wind input....

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  • ...BATSRUS (Powell et al. 1999) selfconsistently coupled with an electric field model (RIM) (Ridley and Liemohn 2002) and driven by dynamic solar wind input....

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Book
01 Jul 1970

927 citations


"The Electric and Magnetic Field Ins..." refers background in this paper

  • ...There are three adiabatic invariants (Roederer 1970) associated with the three basic periodic motions: gyromotion, the bounce motion in the Earth’s magnetic mirror field, and the azimuthal drift due to magnetic gradients....

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Journal ArticleDOI
TL;DR: In this paper, a model was proposed to account for the observed variations in the flux and pitch angle distribution of relativistic electrons during geomagnetic storms by combining pitch angle scattering by intense EMIC waves and energy diffusion during cyclotron resonant interaction with whistler mode chorus outside the plasmasphere.
Abstract: Resonant diffusion curves for electron cyclotron resonance with field-aligned electromagnetic R mode and L mode electromagnetic ion cyclotron (EMIC) waves are constructed using a fully relativistic treatment. Analytical solutions are derived for the case of a single-ion plasma, and a numerical scheme is developed for the more realistic case of a multi-ion plasma. Diffusion curves are presented, for plasma parameters representative of the Earth's magnetosphere at locations both inside and outside the plasmapause. The results obtained indicate minimal electron energy change along the diffusion curves for resonant interaction with L mode waves. Intense storm time EMIC waves are therefore ineffective for electron stochastic acceleration, although these waves could induce rapid pitch angle scattering for ≳ 1 MeV electrons near the duskside plasmapause. In contrast, significant energy change can occur along the diffusion curves for interaction between resonant electrons and whistler (R mode) waves. The energy change is most pronounced in regions of low plasma density. This suggests that whistler mode waves could provide a viable mechanism for electron acceleration from energies near 100 keV to above 1 MeV in the region outside the plasmapause during the recovery phase of geomagnetic storms. A model is proposed to account for the observed variations in the flux and pitch angle distribution of relativistic electrons during geomagnetic storms by combining pitch angle scattering by intense EMIC waves and energy diffusion during cyclotron resonant interaction with whistler mode chorus outside the plasmasphere.

824 citations


"The Electric and Magnetic Field Ins..." refers background in this paper

  • ...the importance of local stochastic acceleration (Summers et al. 1998; Horne and Thorne 1998)....

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  • ...…cause violation of the first two invariants and lead to pitch angle scattering loss to the atmosphere (Thorne and Kennel 1971; Lyons et al. 1972; Abel and Thorne 1998a, 1998b) or local stochastic energy diffusion (Horne and Thorne 1998; Summers et al. 1998; Horne et al. 2005; Miyoshi et al. 2003)....

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  • ...On the other hand, local acceleration involving VLF waves, particularly lower-band chorus, becomes most efficient in the region just outside the plasmapause, which corresponds to the radial range 3–5 RE for storm conditions (Summers et al. 1998; Meredith et al. 2003b)....

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  • ...2005) and local stochastic acceleration (Summers et al. 1998; Horne et al. 2005) along a broad portion of the electron drift path between midnight and noon....

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  • ...1972; Abel and Thorne 1998a, 1998b) or local stochastic energy diffusion (Horne and Thorne 1998; Summers et al. 1998; Horne et al. 2005; Miyoshi et al. 2003)....

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Journal ArticleDOI
TL;DR: In this paper, the formation of the quiet-time electron slot, which divides the radiation belt electrons into an inner and an outer zone, was investigated. But the results were limited to the inner radiation zone.
Abstract: Study of the formation of the quiet-time electron slot, which divides the radiation belt electrons into an inner and an outer zone. The pitch-angle diffusion of radiation belt electrons resulting from resonant interactions with the observed plasmaspheric whistler-mode wave band is quantitatively investigated. The effects of wave propagation obliquely to the geomagnetic field direction with the resulting diffusion at all cyclotron-harmonic resonances and the Landau resonance are evaluated along with the effects of interactions occuring at all geomagnetic latitudes. The results obtained account for the long-term stability of the inner radiation zone, the location of its outer edge as a function of electron energy, and the removal of electrons to levels near zero throughout the slot. Computed pitch-angle distributions and precipitation decay rates are in good agreement with slot-region observations.

760 citations


"The Electric and Magnetic Field Ins..." refers background in this paper

  • ...…cone and lost by collisions in the atmosphere during resonant interactions with whistler-mode chorus emissions (Thorne et al. 2005), plasmaspheric hiss (Lyons et al. 1972; Abel and Thorne 1998a) and electromagnetic ion cyclotron waves (Albert 2003; Summers and Thorne 2003; Jordanova et al. 2008)....

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  • ...…ELF and VLF waves cause violation of the first two invariants and lead to pitch angle scattering loss to the atmosphere (Thorne and Kennel 1971; Lyons et al. 1972; Abel and Thorne 1998a, 1998b) or local stochastic energy diffusion (Horne and Thorne 1998; Summers et al. 1998; Horne et al. 2005;…...

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