Spatial and temporal properties of AKR burst emission derived from Cluster WBD VLBI studies

Mutel, R. L.; Gurnett, D. A.; Christopher, I. W.

doi:10.5194/angeo-22-2625-2004

Cited by 32 publications

(42 citation statements)

References 26 publications

(28 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As a next step we apply moving average filter (20 points corresponding to full 360° antenna system rotation), damping outliers produced by steps with low s/n ratio, or ill‐posed system of equations used for fitting the solutions to data. Resulting positions scatter does not differ much from similar diagrams produced by Mutel et al [], compare their Figure 8b and our Figure 3.…”

Section: Interball‐2—direction Finding and Determination Of Akr Sourcsupporting

confidence: 84%

Beaming of intense AKR seen from the Interball‐2 spacecraft

et al. 2017

View full text Add to dashboard Cite

We present results of intense auroral kilometric radiation (AKR) sources direction finding based on single‐spacecraft truek→ vector source location performed in the frame of Interball‐2 mission (POLRAD experiment on board Auroral Probe). With our swept frequency analyzer we are not able to work with single AKR bursts generated in small, elementary sources, but we improve our signal‐to‐noise (s/n) ratio and determine direction to the AKR source region averaging data over 10 consecutive 4 kHz frequency steps. Measurements of directions to the AKR sources confirm recent Mutel et al. () findings based on Cluster Very Long Baseline Interferometry (VLBI) data—AKR rays are mostly confined to the direction tangent to the auroral oval as measured in Mutel's tangent plane (TP) coordinates. In this paper we use additional coordinate system rotated with respect to TP coordinates in order to determine azimuths of AKR rays with respect to the auroral oval. We see cases of AKR propagation significantly deflected from the tangent plane. Additional information concerning geometry of auroral arc at the AKR source can help to distinguish between propagation along and propagation across the auroral cavity. Examples of instantaneous AKR visibility maps defined in this paper for both coordinate systems are shown and discussed. Using such map (valid for our spacecraft for relatively short observational periods of the order of 10 min), it is possible for known positions of the AKR sources in invariant latitude‐magnetic local time coordinates to visualize direction angles of AKR beams reaching the observer.

show abstract

Section: Interball‐2—direction Finding and Determination Of Akr Sourcsupporting

confidence: 84%

Beaming of intense AKR seen from the Interball‐2 spacecraft

et al. 2017

View full text Add to dashboard Cite

show abstract

“…They found that AKR is generally emitted from individual sources located in the nightside auroral zone (see Fig. 3 in Mutel et al 2004), consistent with previous statistical results. Whether the AKR emission cone is hollow (Benson and Calvert 1979;Calvert 1981), or filled (Green et al 1977;Green and Gallagher 1985) has been debated since the early days of AKR research.…”

Section: Betatron and Stochastic Accelerationsupporting

confidence: 89%

Multipoint observations of plasma phenomena made in space by Cluster

et al. 2015

View full text Add to dashboard Cite

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.

show abstract

“…Then, the goniopolarimetric capabilities of the RPWS High Frequency Receiver (HFR) made it possible to directly determine the SKR Stokes parameters (flux and full polarization state) of observed radio waves and their direction of arrival [ Cecconi and Zarka , 2005]. Similar “direction‐finding” techniques, developed since the 1980s for space observations of the Earth's auroral kilometric radiation (AKR), resulted in the direct mapping of a few AKR events down to discrete UV auroral sources [ Huff et al , 1988; de Feraudy et al , 1988; Panchenko , 2003; Mutel et al , 2004]. Twenty years later, RPWS/HFR goniopolarimetric results were used to infer the SKR source location quasi‐continuously.…”

Section: Introductionmentioning

confidence: 99%

An auroral oval at the footprint of Saturn's kilometric radio sources, colocated with the UV aurorae

et al. 2009

View full text Add to dashboard Cite

Similarly to other magnetized planets, Saturn displays auroral emissions generated by accelerated electrons gyrating around high‐latitude magnetic field lines. They mainly divide in ultraviolet (UV) and infrared (IR) aurorae, excited by electron collisions with the upper atmosphere, and Saturn's kilometric radiation (SKR), radiated from higher altitudes by electron‐wave resonance. Whereas spatially resolved UV and IR images of atmospheric aurorae reveal a continuous auroral oval around each pole, the SKR source locus was only indirectly constrained by the Voyager radio experiment to a limited local time (LT) range on the morningside, leading to interpretation of the SKR modulation as a fixed flashing light. Here, we present resolved SKR maps derived from the Cassini Radio and Plasma Wave Science (RPWS) experiment using goniopolarimetric techniques. We observe radio sources all around the planet, organized along a high‐latitude continuous auroral oval. Observations of the Hubble Space Telescope obtained in January 2004 and January 2007 have been compared to simultaneous and averaged Cassini‐RPWS measurements, revealing that SKR and UV auroral ovals are very similar, both significantly enhanced on the dawnside. These results imply that the SKR and atmospheric aurorae are triggered by the same populations of energetic electron beams, requiring a unified model of particle acceleration and precipitation on Saturn.

show abstract

Spatial and temporal properties of AKR burst emission derived from Cluster WBD VLBI studies

Abstract: Abstract.We have determined the locations of over 6000 individual auroral kilometric radiation (AKR) bursts between

Cited by 32 publications

References 26 publications

Beaming of intense AKR seen from the Interball‐2 spacecraft

Beaming of intense AKR seen from the Interball‐2 spacecraft

Multipoint observations of plasma phenomena made in space by Cluster

An auroral oval at the footprint of Saturn's kilometric radio sources, colocated with the UV aurorae

Contact Info

Product

Resources

About