Journal ArticleDOI
Isis 1 observations at the source of auroral kilometric radiation
Robert F. Benson,Wynne Calvert +1 more
TLDR
In this paper, the auroral kilometric radiation (AKR) was observed from Isis 1 above the nighttime auroral zone over a wider extent in longitude than in latitude with an intense source region observed most often near 2200 LMT and 70 deg invariant latitude.Abstract:
Observations of auroral kilometric radiation (AKR) were made by Isis 1 in the source region. The radiation is found to be generated in the extraordinary mode just above the local cut-off frequency and to emanate nearly perpendicular to the magnetic field. It occurs within local depletions of electron density, where the ratio of plasma frequency to cyclotron frequency is less than 0.2. The density depletion is restricted to altitudes above about 2000 km, and the upper AKR frequency limit corresponds to the extraordinary cut-off frequency at this altitude. AKR is observed from Isis 1 above the nighttime auroral zone over a wider extent in longitude than in latitude with an intense source region observed most often near 2200 LMT and 70 deg invariant latitude. It is directly related to inverted V electron precipitation events with an electron-to-wave energy conversion efficiency of the order of 0.1 to 1%.read more
Citations
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Journal ArticleDOI
Small scale alfvénic structure in the aurora
K. Stasiewicz,P. Bellan,Christopher C. Chaston,Craig Kletzing,Robert L. Lysak,J. Maggs,O. A. Pokhotelov,Charles Seyler,Padma Kant Shukla,Lennart Stenflo,Anatoly V. Streltsov,Jan-Erik Wahlund +11 more
TL;DR: A comprehensive review of dispersive Alfven waves in space and laboratory plasmas is presented in this article, where the authors show how the inclusion of ion gyroradius, parallel electron inertia, and finite frequency effects modify the Alfven wave properties.
Journal ArticleDOI
The electron–cyclotron maser for astrophysical application
TL;DR: The electron-cyclotron maser is a process that generates coherent radiation from plasma as mentioned in this paper, and it has gained increasing attention as a dominant mechanism of producing high-power radiation in natural high-temperature magnetized plasmas.
Journal ArticleDOI
Auroral arc thicknesses as predicted by various theories
TL;DR: In this article, the authors examined 12 electron acceleration mechanisms and 10 generator mechanisms for auroral arcs, and a characteristic auroral-arc thickness was worked out for each mechanism except one, and the arc thicknesses were then mapped down to the ionosphere along the terrestrial magnetic field lines; near the Earth, a dipole magnetic field model was used, and farther from the Earth the mapping included the effects of magnetic field-line draping.
Journal ArticleDOI
The auroral plasma cavity
TL;DR: A region of diminished plasma density has been found to occur at the source of auroral kilometric radiation (AKR) at 70 deg + or - 3 deg invariant magnetic latitude as discussed by the authors.
Journal ArticleDOI
Auroral hiss, Z-mode radiation and auroral kilometric radiation in the polar magnetosphere: DE-1 observations
TL;DR: The first measurements of high-latitude auroral phenomena were provided by the polar-orbiting DE 1 spacecraft as mentioned in this paper, where three types of plasma-wave emissions were observed: auroral hiss, Z-mode radiation, and auroral kilometric radiation.
References
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Journal ArticleDOI
A theory of the terrestrial kilometric radiation
C. S. Wu,Lou-Chuang Lee +1 more
TL;DR: In this paper, it was found that reflected electrons can result in the amplification of electromagnetic waves via a relativistic normal cyclotron resonance, which may explain the recently discovered terrestrial kilometric radiation.
Journal ArticleDOI
Observations of paired electrostatic shocks in the polar magnetosphere
F. S. Mozer,C. W. Carlson,Mary K. Hudson,Roy B. Torbert,B. Parady,J. Yatteau,Michael C. Kelley +6 more
TL;DR: In this article, a polar orbiting satellite was used to measure spatially confined regions of extremely large electric fields in the auroral zone at altitudes below 8000 km, which are identified as paired electrostatic shocks which are associated with electrostatic ion cyclotron wave turbulence.
Journal ArticleDOI
The Earth as a radio source: Terrestrial kilometric radiation
TL;DR: In this article, the Earth appears to be a very intense planetary radio source, with a total power output comparable to the decametric radio emission from Jupiter, and the terrestrial kilometric radiation seems to originate from low altitudes in the auroral region.
Journal ArticleDOI
The angular distribution of auroral kilometric radiation
TL;DR: In this article, a study based on data from Hawkeye 1, Imp 6 and Imp 8 satellites has shown that the intense kilometric radio emissions generated over the nightside auroral regions are beamed into a cone-shaped region whose axis of symmetry is tilted away from the magnetic axis of the earth, toward evenings, by about 20 degrees.
Journal ArticleDOI
On the polarization and origin of auroral kilometric radiation
Donald A. Gurnett,James L. Green +1 more
TL;DR: In this paper, the authors used the Hawkeye 1 spacecraft to observe the auroral kilometric radiation at radial distances of about 2.0 R(E) over the southern hemisphere and found that it has a sharply defined low-altitude cutoff at the altitude where the local electron gyrofrequency is equal to the wave frequency.