Pitch angle distribution of relativistic electrons in the inner radiation belt and its relation to equatorial plasma wave turbulence phenomena

Morioka, A.; Misawa, Hiroaki; Miyoshi, Y.; Oya, Hiroshi; Iizima, M.; Nagai, T.

doi:10.1029/2000gl011886

Cited by 11 publications

(14 citation statements)

References 13 publications

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“…The displayed data sets were restricted to the observation in the dawn sector of the southern hemisphere. Before the storm (phase A), the pitch angle distributions of the radiation belt electrons were consistent with the statistical picture reported by Morioka et al [2001]. The pitch angle distribution in the outer radiation belt showed the slight pancake distribution.…”

Section: Energetic Particle Observationssupporting

confidence: 86%

Rebuilding process of the outer radiation belt during the 3 November 1993 magnetic storm: NOAA and Exos‐D observations

2003

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[1] Using the data from the NOAA and Exos-D satellites during the 3 November 1993 magnetic storm, the dynamic behavior of electrons with energies from a few tens of kiloelectronvolts to a few and its relation to plasma waves were examined. After the late main phase, relativistic electron flux started to recover from the heart of the outer radiation belt, where the cold plasma density was extremely low, and intense whistler mode chorus emissions were detected. The phase space density showed a peak in the outer belt, and the peak increased gradually. The simulation of the inward radial diffusion process could not reproduce the observed energy spectrum and phase space density variation. On the other hand, the simulated energy diffusion due to the gyroresonant electronwhistler mode wave interactions, under the assumption of the Kolmogorov turbulence spectrum, could generate the relativistic electrons without the flux transport from the outer region. The present study suggested that the seed population of relativistic electrons, which appeared in the heart of the outer radiation belt during the late main phase, was the ring current electrons injected from the plasma sheet, and that the acceleration by whistler mode chorus via gyroresonant wave-particle interactions outside the plasmapause could play an important role to generate the relativistic electrons.

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Section: Energetic Particle Observationssupporting

confidence: 86%

Rebuilding process of the outer radiation belt during the 3 November 1993 magnetic storm: NOAA and Exos‐D observations

2003

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“…A brief list of such phenomena include: electron precipitation coincident with ELF/VLF wave bursts (Walt et al, 2002); ULF modulation of energetic particles in the dayside magnetosphere (Zong et al, 2007); electron micro-bursts in association with chorus (Lorentzen, 2001); acceleration and loss depending on plasmaspheric hiss (Meredith et al, 2004); precipitation of radiation belt electrons induced by whistlers (Lauben et al, 2001); electron precipitation induced by magnetospheric reflected whistler waves (Bortnik et al, 2006); pitch-angle scattering by electromagnetic ion cyclotron waves (Summers and Thorne, 2003). Some mechanical wave interactions were investigated: acceleration by fast magnetosonic waves (Horne et al, 2007) and electrons precipitation in relation to equatorial plasma wave turbulence phenomena (Morioka et al, 2001). Furthermore, there are some kinds of electromagnetic waves coming from the surface of the earth, such as anthropogenic noise and natural emissions.…”

Section: Introductionmentioning

confidence: 99%

Analysis of NOAA particle data and correlations to seismic activity

Fidani

Battiston

2008

Nat. Hazards Earth Syst. Sci.

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Abstract.A decade of NOAA-15 particle flux data offers an opportunity to test claims of correlations between seismic activity and effects on the ionosphere. Over the last two decades, potentially interesting observations in the ionosphere-magnetosphere transition region have been investigated. Specifically these consists of anomalous particle fluxes detected by several space experiments and correlated with the earthquake occurrence. These particle fluxes are characterised by anomalous short-term and sharp increases in high energy particle counting rates, referred to as particle bursts. In this work, more general rules for particle bursts selection have been defined and tested on the NOAA database, for particles inside and outside the South Atlantic Anomaly region. The whole period of ten years burst activity from NOAA-15 database is reported. Data from four satellites, NOAA-15, 16, 17 and 18, were analyzed during periods of solar quiet activity in connection with strong earthquakes, revealing presence of bursts detected on more than one satellite close to the time of the same seismic events. This preliminary study presented here concentrates on periods of major Indonesian earthquakes from 1998 to date, including Sumatra event M=9, during which geomagnetic Ap index was less than 16 and with no sudden ionospheric disturbances. During this period particle burst temporal distributions have shown some correspondence with earthquake times. The limits of the analysis presented in this papers are discussed as well as prospects for future work.

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“…Usually, the pitch angle distribution is influenced by the effects of plasma wave turbulence and particle/wave resonance. The inner belt measurements by Morioka et al [2001] show that in the magnetic equator region with low L (L ∼ 2) the dumbbell distribution of 0.3-2.5 MeV electrons appears to be relatively stable, contrary to what measured at higher magnetic latitudes. A typical case is shown by Horne et al [2003] presenting the case of a significant change from pancake to dumbbell electron distributions in the range 0.1-2 MeV during the 9-15 October 1990 storm.…”

Section: Discussionmentioning

confidence: 75%

“…Other magnetospheric probes measured the steady state and transient properties of the pitch angle distribution near the magnetic equator [e.g., Morioka et al, 2001;Horne et al, 2003;Xiao et al, 2009]. Usually, the pitch angle distribution is influenced by the effects of plasma wave turbulence and particle/wave resonance.…”

Section: Discussionmentioning

confidence: 99%

“…This spectral behavior confirms the trend inferred from the previous observations of Alpha Magnetic Spectrometer (AMS)-Shuttle Flight [Alcaraz et al, 2000] and MARYA [Koldashov et al, 1995] and discussed in Longo et al [2002] in regard to the charged particle flux profile along the AGILE orbit. This behavior is associated to acceleration mechanisms by resonant interactions in the ionosphere/magnetosphere transition region (see Morioka et al [2001] for a discussion of inner magnetosphere data; for a general theoretical treatment see also Summers et al [1998]). The sub-ERB particle radiation is characterized by a flux modulation coherent with the solar cycle Malakhov et al, 2015].…”

Section: Introductionmentioning

confidence: 99%

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AGILE as a particle detector: Magnetospheric measurements of 10–100 MeV electrons in L shells less than 1.2

et al. 2016

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We study the capability of the AGILE gamma ray space mission in detecting magnetospheric particles (mostly electrons) in the energy range 10–100 MeV. Our measurements focus on the inner magnetic shells with L0.3em≲0.3em1.2 in the magnetic equator. The instrument characteristics and a quasi‐equatorial orbit of ∼500 km altitude make it possible to address several important properties of the particle populations in the inner magnetosphere. We review the on board trigger logic and study the acceptance of the AGILE instrument for particle detection. We find that the AGILE effective geometric factor (acceptance) is R≃50 cm2 sr for particle energies in the range 10–100 MeV. Particle event reconstruction allows to determine the particle pitch angle with the local magnetic field with good accuracy. We obtain the pitch angle distributions for both the AGILE “pointing” phase (July 2007 to October 2009) and the “spinning” phase (November 2009 to present). In spinning mode, the whole range (0–180 degrees) is accessible every 7 min. We find a pitch angle distribution of the “dumbbell” type with a prominent depression near α = 90° which is typical of wave‐particle resonant scattering and precipitation in the inner magnetosphere. Most importantly, we show that AGILE is not affected by solar particle precipitation events in the magnetosphere. The satellite trajectory intersects magnetic shells in a quite narrow range ( 1.00.3em0.3em≲0.3em0.3emL0.3em0.3em≲0.3em0.3em1.2); AGILE then has a high exposure to a magnetospheric region potentially rich of interesting phenomena. The large particle acceptance in the 10–100 MeV range, the pitch angle determination capability, the L shell exposure, and the solar‐free background make AGILE a unique instrument for measuring steady and transient particle events in the inner magnetosphere.

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Pitch angle distribution of relativistic electrons in the inner radiation belt and its relation to equatorial plasma wave turbulence phenomena

Cited by 11 publications

References 13 publications

Rebuilding process of the outer radiation belt during the 3 November 1993 magnetic storm: NOAA and Exos‐D observations

Rebuilding process of the outer radiation belt during the 3 November 1993 magnetic storm: NOAA and Exos‐D observations

Analysis of NOAA particle data and correlations to seismic activity

AGILE as a particle detector: Magnetospheric measurements of 10–100 MeV electrons in L shells less than 1.2

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