Magnetic field power spectra and magnetic radial diffusion coefficients using CRRES magnetometer data

Ali, A.; Elkington, S. R.; Tu, Weichao; Ozeke, L. G.; Chan, A. A.; Friedel, R. H. W.

doi:10.1002/2014ja020419

Cited by 29 publications

(83 citation statements)

References 80 publications

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“…8 in this article). This is confirmed by CRRES data (Ali et al, 2015): in the range of ∼ 1-8 mHz averaged spectra of the magnetic field fluctuations are very hard and almost flat.…”

Section: Discussionsupporting

confidence: 73%

“…The spectra of the fluctuations of magnetic and electric fields in the range of ULF were also obtained from satellites (e.g., Lanzerotti et al, 1978;Holzworth and Mozer, 1979;Lanzerotti and Wolfe, 1980;Ali et al, 2015). The results of these estimates of D LL differ from each other by several orders of magnitude.…”

Section: Introductionmentioning

confidence: 99%

“…On the basis of spectra of pulsations of the magnetic and electric fields in the range of ULF (Pc4-Pc5), values of D LL have been calculated in many recent works (e.g., Tu et al, 2012;Ozeke et al, 2012Ozeke et al, , 2014Ali et al, 2015;Liu et al, 2016). For this purpose, data from the Geostationary Operational Environmental Satellite (GOES), Active Magnetospheric Particle Tracer Explorers (AMPTE), the Combined Release and Radiation Effects Satellite (CRRES), the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission, Van Allen Probes, etc., for spectra of pulsations are used.…”

Section: Introductionmentioning

confidence: 99%

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Deduction of the rates of radial diffusion of protons from the structure of the Earth's radiation belts

Kovtyukh

2016

Ann. Geophys.

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Abstract. From the data on the fluxes and energy spectra of protons with an equatorial pitch angle of α 0 ≈ 90 • during quiet and slightly disturbed (Kp ≤ 2) periods, I directly calculated the value D LL , which is a measure of the rate of radial transport (diffusion) of trapped particles. This is done by successively solving the systems (chains) of integrodifferential equations which describe the balance of radial transport/acceleration and ionization losses of low-energy protons of the stationary belt. This was done for the first time. For these calculations, I used data of International SunEarth Explorer 1 (ISEE-1) for protons with an energy of 24 to 2081 keV at L = 2-10 and data of Explorer-45 for protons with an energy of 78.6 to 872 keV at L = 2-5. Ionization losses of protons (Coulomb losses and charge exchange) were calculated on the basis of modern models of the plasmasphere and the exosphere. It is shown that for protons with µ from ∼ 0.7 to ∼ 7 keV nT −1 at L≈ 4.5-10, the functions of D LL can be approximated by the following equivalent expressions:, where f d is the drift frequency of the protons (in mHz), D LL is measured in s −1 , E is measured in kiloelectronvolt and µ is measured in kiloelectronvolt per nanotesla. These results are consistent with the radial diffusion of particles under the action of the electric field fluctuations (pulsations) in the range of Pc6 and contradict the mechanism of the radial diffusion of particles under the action of sudden impulses (SIs) of the magnetic field and also under the action of substorm impulses of the electric field. During magnetic storms D LL increases, and the expressions for D LL obtained here can change completely.

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“…8 in this article). This is confirmed by CRRES data (Ali et al, 2015): in the range of ∼ 1-8 mHz averaged spectra of the magnetic field fluctuations are very hard and almost flat.…”

Section: Discussionsupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Deduction of the rates of radial diffusion of protons from the structure of the Earth's radiation belts

Kovtyukh

2016

Ann. Geophys.

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“…Other techniques to determine D L L include analysis of radial transport directly from radiation belt electron measurements assuming no other processes such as local heating intervene [ Selesnick et al , ]; calculation from electric field fluctuations [ Brautigam et al , ] and magnetic field fluctuations [ Ali et al , ] measured in situ; and a combination of ground magnetometer measurements of the transverse magnetic field components, which can be related to equatorial plane transverse electric field assuming a standing Alfven wave model and combined with in situ measurements of the compressional magnetic field fluctuations [ Ozeke et al , ]. In our study, the radial diffusion coefficient is calculated from LFM MHD simulations using the formula from Fei et al [], in which the diffusion coefficient is proportional to the integral of the fluctuating electric and magnetic field power that could resonate with the electron drift frequency.…”

Section: Introductionmentioning

confidence: 99%

Global ULF wave analysis of radial diffusion coefficients using a global MHD model for the 17 March 2015 storm

et al. 2016

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The 17–18 March 2015 storm is the largest geomagnetic storm in the Van Allen Probes era to date. The Lyon‐Fedder‐Mobarry global MHD model has been run for this event using ARTEMIS data as solar wind input. The ULF wave power spectral density of the azimuthal electric field and compressional magnetic field is analyzed in the 0.5–8.3 mHz range. The lowest three azimuthal modes account for 70% of the total power during quiet times. However, during high activity, they are not exclusively dominant. The calculation of the radial diffusion coefficient is presented. We conclude that the electric field radial diffusion coefficient is dominant over the magnetic field coefficient by one to two orders of magnitude. This result contrasts with the dominant magnetic field diffusion coefficient used in most 3‐D diffusion models.

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“…The first comprehensive studies of ULF waves inward of the geostationary orbit were made using observations by the Active Magnetospheric Particle Tracer Explorers (AMPTE)/Charge Composition Explorer (CCE) at 5-8 R E (R E is the radius of the earth) (Anderson et al 1990;Anderson 1994). Ali et al (2015) investigated ULF waves observed by the Combined Release and Radiation Effects Satellite (CRRES) at L = 4-6.5 and evaluated the radial diffusion coefficient. The contribution of ULF waves to relativistic electron generation is still controversial; Su et al (2015) concluded that radial diffusion plays a key role, whereas a substantial number of studies support gyroresonant electron-whistler mode wave interaction as the predominant process (Miyoshi et al 2003;Horne et al 2005a, b;Shprits et al 2008;Reeves et al 2013 and references therein).…”

Section: Pc3-5 Ultra-low-frequency Wavesmentioning

confidence: 99%

The ARASE (ERG) magnetic field investigation

Matsuoka

Teramoto

Nomura

et al. 2018

Earth Planets Space

140

156

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The fluxgate magnetometer for the Arase (ERG) spacecraft mission was built to investigate particle acceleration processes in the inner magnetosphere. Precise measurements of the field intensity and direction are essential in studying the motion of particles, the properties of waves interacting with the particles, and magnetic field variations induced by electric currents. By observing temporal field variations, we will more deeply understand magnetohydrodynamic and electromagnetic ion-cyclotron waves in the ultra-low-frequency range, which can cause production and loss of relativistic electrons and ring-current particles. The hardware and software designs of the Magnetic Field Experiment (MGF) were optimized to meet the requirements for studying these phenomena. The MGF makes measurements at a sampling rate of 256 vectors/s, and the data are averaged onboard to fit the telemetry budget. The magnetometer switches the dynamic range between ± 8000 and ± 60,000 nT, depending on the local magnetic field intensity. The experiment is calibrated by preflight tests and through analysis of in-orbit data. MGF data are edited into files with a common data file format, archived on a data server, and made available to the science community. Magnetic field observation by the MGF will significantly improve our knowledge of the growth and decay of radiation belts and ring currents, as well as the dynamics of geospace storms.

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Magnetic field power spectra and magnetic radial diffusion coefficients using CRRES magnetometer data

Cited by 29 publications

References 80 publications

Deduction of the rates of radial diffusion of protons from the structure of the Earth's radiation belts

Deduction of the rates of radial diffusion of protons from the structure of the Earth's radiation belts

Global ULF wave analysis of radial diffusion coefficients using a global MHD model for the 17 March 2015 storm

The ARASE (ERG) magnetic field investigation

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