Striated auroral kilometric radiation emission: A remote tracer of ion solitary structures

Mutel, R. L.; Menietti, J. D.; Christopher, I. W.; Gurnett, D. A.; Cook, J. M.

doi:10.1029/2006ja011660

Cited by 36 publications

(70 citation statements)

References 51 publications

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“…While it may be reasonable to regard commonly observed AKR generally as ensembles of emissions from distributions of 'elemental radiators' (Pottelette et al 2001), it is not clear if all AKR is comprised of only SAKR bursts. The observations reported by Mutel et al (2006) showed that SAKR appeared as negatively drifting features (df/dt < 0) superposed on regular broadband AKR background. These observations suggest that the SAKR-producing structures are ion holes moving upward through coeval AKR sources, although this scenario does not account for the upward (df/dt > 0) or nearly constant (df/dt ∼ 0) spectral striations seen in earlier observations (Gurnett et al 1979;Gurnett and Anderson 1981;Menietti et al 1996Menietti et al , 2000.…”

Section: Betatron and Stochastic Accelerationmentioning

confidence: 99%

“…However, the Cluster ESW propagation studies prove that ESWs are not intrinsically unstable, which helps to bound the problem when considering how they are generated. This was an important issue in the study by Mutel et al (2006), which concluded that ion solitary waves passing through the AKR generation region affected the CMI, leading to the striations discussed above.…”

Section: Electrostatic Solitary Wavesmentioning

confidence: 99%

“…The narrow bandwidths and negative frequency drifts of individual SAKR bursts observed by Cluster suggest that SAKR sources are compact (≈1 km extent along the auroral field line) and are moving upward along the field with speeds comparable to the ion-acoustic speed. These observations led Mutel et al (2006) to conclude that SAKR sources are upward propagating small-scale ion holes or ESWs that can modify the electron distributions in AKR source regions to produce enhanced narrowband emissions over the regular broadband AKR background. Mutel et al (2006) analyzed 651 individual SAKR bursts and determined statistically that an SAKR beam at 125-135 kHz has a FWHM width of 5 • (solid angle Ω = 0.006 sr), which is much narrower than the ensemble-averaged AKR emission cone sizes of 4.6 sr at 178 kHz and 3.3 sr at 100 kHz reported by Green and Gallagher (1985).…”

Section: Betatron and Stochastic Accelerationmentioning

confidence: 99%

“…These observations led Mutel et al (2006) to conclude that SAKR sources are upward propagating small-scale ion holes or ESWs that can modify the electron distributions in AKR source regions to produce enhanced narrowband emissions over the regular broadband AKR background. Mutel et al (2006) analyzed 651 individual SAKR bursts and determined statistically that an SAKR beam at 125-135 kHz has a FWHM width of 5 • (solid angle Ω = 0.006 sr), which is much narrower than the ensemble-averaged AKR emission cone sizes of 4.6 sr at 178 kHz and 3.3 sr at 100 kHz reported by Green and Gallagher (1985). While it may be reasonable to regard commonly observed AKR generally as ensembles of emissions from distributions of 'elemental radiators' (Pottelette et al 2001), it is not clear if all AKR is comprised of only SAKR bursts.…”

Section: Betatron and Stochastic Accelerationmentioning

confidence: 99%

“…Menietti et al (2006) pointed out that electrons holes are more abundantly observed in downward current regions, so they would be less likely to be responsible for generating AKR emissions, which is thought to be produced in upward fieldaligned current regions. Mutel et al (2006) proposed that ion holes, rather than electron holes or tripolar structures, are the source of AKR ordered fine structure. Analyzing Cluster WBD observations of ordered AKR fine structure and electron distributions taken by the Polar HYDRA instrument near magnetic conjunction, Menietti et al (2006) found that the unstable electron horseshoe distributions in/near the AKR source region can also produce electromagnetic ion cyclotron (EMIC) waves.…”

Section: Betatron and Stochastic Accelerationmentioning

confidence: 99%

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Multipoint observations of plasma phenomena made in space by Cluster

et al. 2015

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Plasmas are ubiquitous in nature, surround our local geospace environment, and permeate the universe. Plasma phenomena in space give rise to energetic particles, the aurora, solar flares and coronal mass ejections, as well as many energetic phenomena in interstellar space. Although plasmas can be studied in laboratory settings, it is often difficult, if not impossible, to replicate the conditions (density, temperature, magnetic and electric fields, etc.) of space. Single-point space missions too numerous to list have described many properties of near-Earth and heliospheric plasmas as measured both in situ and remotely (see http://www.nasa.gov/missions/#.U1mcVmeweRY for a list of NASA-related missions). However, a full description of our plasma environment requires three-dimensional spatial measurements. Cluster is the first, and until data begin flowing from the Magnetospheric Multiscale Mission (MMS), the only mission designed to describe the three-dimensional spatial structure of plasma phenomena in geospace. In this paper, we concentrate on some of the many plasma phenomena that have been studied using data from Cluster. To date, there have been more than 2000 refereed papers published using Cluster data but in this paper we will, of necessity, refer to only a small fraction of the published work. We have focused on a few basic plasma phenomena, but, for example, have not dealt with most of the vast body of work describing dynamical phenomena in Earth's magnetosphere, including the dynamics of current sheets in Earth's magnetotail and the morphology of the dayside high latitude cusp. Several review articles and special publications are available that describe aspects of that research in detail and interested readers are referred to them (see for example, Escoubet et al.

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Section: Betatron and Stochastic Accelerationmentioning

confidence: 99%

Section: Electrostatic Solitary Wavesmentioning

confidence: 99%

Section: Betatron and Stochastic Accelerationmentioning

confidence: 99%

Section: Betatron and Stochastic Accelerationmentioning

confidence: 99%

Section: Betatron and Stochastic Accelerationmentioning

confidence: 99%

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Multipoint observations of plasma phenomena made in space by Cluster

et al. 2015

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Further evidence for a connection between auroral kilometric radiation and ground‐level signals measured in Antarctica

et al. 2015

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(2015), Further evidence for a connection between auroral kilometric radiation and ground-level signals measured in Antarctica, J. Geophys. Res. Space Physics, 120, 2061-2075, doi:10.1002 Polarization measurements of one event show it to be right-hand polarized. Correlation analysis of ground-level and satellite data suggests an imperfect correlation with 2-3 sigma significance, although occasionally much better. (Perfect correlation is not expected, for at least two reasons: distant satellites detect AKR from many sources over a significant part of the oval, and many effects can hinder transmission of AKR from those sources to either distant satellites or ground stations.) Statistical analysis of the existing quantity of data is therefore suggestive but does not prove a connection between the ground-level AKR-like signals and outgoing AKR. However, two other methods provide evidence favoring such a connection. The first full-resolution measurements of ground-level AKR-like signals show that their fine structure strongly resembles that of AKR as known from high-resolution spacecraft receivers. Two case studies show that the location of active aurora, presumed connected with the AKR sources, controls whether or not the ground station detects the AKR, or which of several ground stations detects it most strongly. These investigations strengthen the hypothesis that through some mechanism, sources of outgoing AKR detected by distant satellites occasionally generate signals detectable as whistler mode waves at low altitude or right-hand polarized signals at ground level.

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