The Kilometric Radio Emission Spectrum: Relationship to Auroral Acceleration Processes

Gurnett, D. A.; Anderson, R. R.

doi:10.1029/gm025p0341

Cited by 74 publications

(17 citation statements)

References 23 publications

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“…The challenges of the statistical correlation approach motivates alternative methods of establishing connections between ground‐level AKR‐like signals and outgoing AKR observed in space. AKR observed in space is characterized by distinctive fine structure, first reported by Gurnett and Anderson [] and subject of many papers since then [e.g., Morioka et al , ; Baumback and Calvert , ; Benson et al , ; Menietti et al , ; Mutel et al , ]. To look for this signature in the ground‐level data, in austral winter 2013 Dartmouth installed the dual SPS‐DSP receiver, described above, at South Pole Station to obtain full resolution with relatively high sensitivity in a relatively narrow band, 330–660 kHz, which is within the AKR frequency range.…”

Section: Fine Structure Studiesmentioning

confidence: 99%

“…Figure e shows this structure fairly clearly, and Figure d shows an expanded view of 300 s of a 65 kHz band of the ground‐level AKR emissions, in which several upward tones are visible at the beginning and end of the record, and a large V‐shaped structure in the middle at 1110–1240 s after 0200 UT. For reference, Figures a and b show spectrograms recorded by the wideband plasma wave instrument [ Gurnett et al , ] on two Cluster spacecraft on 15 January 2010 (D. Menietti, personal communication, 2015), and Figure c is a reprint of a spectrogram recorded on 24 January 1978 by the University of Iowa wideband wave instrument on the ISEE‐1 spacecraft, reprinted from Gurnett and Anderson []; both of these examples have been cropped and resized such that the frequency and time scales match those of the expanded view of the South Pole event. The AKR measured in space has fine structure with characteristics very similar to those observed in the ground‐level AKR: a V‐shaped structures with roughly the same timescale and upward trending tones with roughly the same slope as observed in the ground‐level AKR.…”

Section: Fine Structure Studiesmentioning

confidence: 99%

“…Bandwidths of the ground‐level AKR signals range from less than 300 Hz to greater than 20 kHz. Assuming generation at the electron cyclotron frequency, observed frequency‐time slopes can be interpreted as motions of the sources in the Earth's magnetic field, using equation (6) of Gurnett and Anderson []. For the ground‐level AKR signals, radial speeds calculated in this way range from nearly flat to 160 km/s, spanning almost the same range as those inferred from spacecraft data [e.g., Gurnett and Anderson , , Figure 9].…”

Section: Fine Structure Studiesmentioning

confidence: 99%

“…Figure d shows an expanded view. For comparison, other panels show typical fine structure of AKR measured by wave receivers on the (a and b) Cluster and (c) ISEE spacecraft, the latter reprinted from Gurnett and Anderson [].…”

Section: Fine Structure Studiesmentioning

confidence: 99%

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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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Section: Fine Structure Studiesmentioning

confidence: 99%

Section: Fine Structure Studiesmentioning

confidence: 99%

Section: Fine Structure Studiesmentioning

confidence: 99%

Section: Fine Structure Studiesmentioning

confidence: 99%

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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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“…Cluster observations have improved our understanding of the fine structure of AKR that was first observed by ISEE 1 and 2 (Gurnett et al 1979;Gurnett and Anderson 1981) and Dynamics Explorer 1, Galileo, and Polar (Menietti et al 1996(Menietti et al , 2000. Fine structure, or striated, AKR (SAKR) consists of narrowband drifting spectral features with wave frequency increasing, remaining relatively constant, or decreasing with time.…”

Section: Betatron and Stochastic Accelerationmentioning

confidence: 99%

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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Initial deflection of middle‐latitude Pi2 pulsations in the premidnight sector: Remote detection of oscillatory upward field‐aligned current at substorm onset

et al. 2016

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In this study, we examined middle‐ and low‐latitude Pi2 events to address the following two issues regarding the well‐known substorm current wedge (SCW) model for Pi2 pulsations: (1) the center of the SCW, which is estimated using the Pi2 polarization pattern, is not always collocated with that determined using the magnetic bay pattern; and (2) although ideally Pi2 hodograms would be linear, they tend to become circular. In this study, auroral breakup events were identified from Polar Ultraviolet Imager data. We assumed that the ionospheric footprint of the upward field‐aligned current (FAC) in each event was located at the position of the auroral breakup and subsequently calculated the signature of the magnetic variation at the middle‐latitude station Zyryanka (ZYK; GMLAT = 59.6°) that was generated by the upward FAC. In order to examine the magnetic effects of the upward FAC, we selected Pi2 events that were observed when ZYK was located on the duskward side of the auroral breakup location. A total of 112 events were selected and analyzed in this study. It was found that the location of the upward FAC of the SCW could be estimated more accurately by using an azimuth value predicted based on the initial deflection of the middle‐latitude Pi2. Our results suggest that the circular shapes of Pi2 polarization curves are caused by the delayed driven Alfvénic waves that are superimposed on the geomagnetic northward components of SCW oscillations.

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The Kilometric Radio Emission Spectrum: Relationship to Auroral Acceleration Processes

Cited by 74 publications

References 23 publications

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

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

Multipoint observations of plasma phenomena made in space by Cluster

Initial deflection of middle‐latitude Pi2 pulsations in the premidnight sector: Remote detection of oscillatory upward field‐aligned current at substorm onset

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