Survey of ELF-VLF plasma waves in outer radiation belt observed by Cluster STAFF-SA experiment

Pokhotelov, Dimitry; Lefeuvre, F.; Horne, Richard B.; Cornilleau‐Wehrlin, N.

doi:10.5194/angeo-26-3269-2008

Cited by 29 publications

(54 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Only the data corresponding to EN with low ellipticity of the magnetic field polarization are selected and included in this study. This was not possible in the previous studies [ Green et al , ; Meredith et al , ; Pokhotelov et al , ] which consider only the PSD in a given interval of frequencies and latitudes.…”

Section: Discussionmentioning

confidence: 93%

Systematic analysis of occurrence of equatorial noise emissions using 10 years of data from the Cluster mission

et al. 2015

Self Cite

View full text Add to dashboard Cite

We report results of a systematic analysis of equatorial noise (EN) emissions which are also known as fast magnetosonic waves. EN occurs in the vicinity of the geomagnetic equator at frequencies between the local proton cyclotron frequency and the lower hybrid frequency. Our analysis is based on the data collected by the Spatio‐Temporal Analysis of Field Fluctuations–Spectrum Analyzer instruments on board the four Cluster spacecraft. The data set covers the period from January 2001 to December 2010. We have developed selection criteria for the visual identification of these emissions, and we have compiled a list of more than 2000 events identified during the analyzed time period. The evolution of the Cluster orbit enables us to investigate a large range of McIlwain's parameter from about L∼1.1 to L∼10. We demonstrate that EN can occur at almost all analyzed L shells. However, the occurrence rate is very low (<6%) at L shells below L=2.5 and above L=8.5. EN mostly occurs between L=3 and L=5.5, and within 7° of the geomagnetic equator, reaching 40% occurrence rate. This rate further increases to more than 60% under geomagnetically disturbed conditions. Analysis of occurrence rates as a function of magnetic local time (MLT) shows strong variations outside of the plasmasphere (with a peak around 15 MLT), while the occurrence rate inside the plasmasphere is almost independent on MLT. This is consistent with the hypothesis that EN is generated in the afternoon sector of the plasmapause region and propagates both inward and outward.

show abstract

Section: Discussionmentioning

confidence: 93%

Systematic analysis of occurrence of equatorial noise emissions using 10 years of data from the Cluster mission

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…Note that another parameter, the dipole L , has been used in many previous studies of whistler mode chorus based on the measurements of the CRRES spacecraft [ Meredith et al , 2001, 2002, 2003a, 2003b, 2009], or the Double Star and CLUSTER spacecraft [ Santolík et al , 2005; Pokhotelov et al , 2008]. It is defined as where R is the radial distance and λ m is the magnetic latitude.…”

Section: Discussionmentioning

confidence: 99%

Survey of Poynting flux of whistler mode chorus in the outer zone

et al. 2010

View full text Add to dashboard Cite

We present a survey of whistler mode chorus emissions based on high‐telemetry rate data of the Plasma Wave Instrument on board the Polar spacecraft. Using simultaneous measurements of full vectors of the electric field and the magnetic field we calculate the Poynting vectors of chorus, and we parameterize the observations by their L* coordinate. Our new analysis of the angle between the direction of the Poynting vector and the magnetic field line confirms previous results on propagation of the main chorus band away from the equator. Our systematic results also prove the existence of the magnetospherically reflected component of chorus found previously by case studies. We observe weak outer zone waves that propagate toward the equator. These waves can be attributed to a poleward reflected component of equatorial chorus or chorus generated in the dayside pockets of a low magnetic field strength. We analyze the probability distribution of the Poynting flux of chorus, and we find that it shows a “heavy tail” feature that can be modeled by a power law or lognormal model. This result has consequences for theories of chorus generation and for methods of statistical characterization of chorus intensities in the frame of radiation belt modeling. We find that the Poynting flux of dayside chorus increases with L* toward the outer zone at L* > 6. We estimate that approximately 1% of the Poynting flux of chorus in the outer zone could be sufficient to accelerate electrons in the outer Van Allen radiation belt on the timescale of days.

show abstract

“…MS waves are primarily confined within ∼2°–3° of the geomagnetic equator [ Russell et al , 1970; Santolík et al , 2002; Nemec et al , 2005, 2006], and occur both inside and outside the plasmapause in the range L ∼ 2–7 [ Gurnett , 1976; Perraut et al , 1982; Laakso et al , 1990], preferentially in the postnoon or dusk sector [ Green et al , 2005; Pokhotelov et al , 2008]. Typical observations show that MS waves occur as a series of narrow tones, spaced at multiples of the proton gyrofrequency ( f ci ), in the range between f ci and the lower hybrid resonance frequency ( f LHR ).…”

Section: Introductionmentioning

confidence: 99%

Transit time scattering of energetic electrons due to equatorially confined magnetosonic waves

2010

View full text Add to dashboard Cite

[1] Recent analysis using quasilinear theory (QLT) has shown that magnetosonic (MS) waves are able to accelerate electrons to relativistic energies on fast time scales (∼1 day). However, the large obliquity of the wave and typical equatorial confinement of the MS wave power create conditions that bring into question the fundamental applicability of QLT to this problem. In this paper, a test particle code is used to model the interaction of energetic electrons with fast MS waves, to test the results of QLT analysis, and to investigate any potential nonlinear effects. It is found that in the expected Landau-resonant region, test particle results show good agreement with QLT, but outside this region, the spatial confinement of the low-frequency waves introduces a new source of scattering which we call "transit time diffusion." Although this mechanism is weaker than resonant scattering, it is nevertheless able to interfere with the Landau resonance to create nulls in the energy-pitch angle diffusion map, and the scattering persists even when resonant diffusion is completely removed.Citation: Bortnik, J., and R. M. Thorne (2010), Transit time scattering of energetic electrons due to equatorially confined magnetosonic waves,

show abstract

Survey of ELF-VLF plasma waves in outer radiation belt observed by Cluster STAFF-SA experiment

Cited by 29 publications

References 37 publications

Systematic analysis of occurrence of equatorial noise emissions using 10 years of data from the Cluster mission

Systematic analysis of occurrence of equatorial noise emissions using 10 years of data from the Cluster mission

Survey of Poynting flux of whistler mode chorus in the outer zone

Transit time scattering of energetic electrons due to equatorially confined magnetosonic waves

Contact Info

Product

Resources

About