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Pfaff, R.; Carlson, C. W.; Watzin, James G.; Everett, David L.; Gruner, T.

doi:10.1023/a:1013187826070

Cited by 27 publications

(7 citation statements)

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“…[8] The FAST satellite was launched in 1996 and operated until March 2009 [Pfaff et al, 2001;Harvey et al, 2001]. It carried a fluxgate magnetometer and 4 electrostatic analyzers that measure particles of energies from a few eV to $30 keV, with the highest time resolution of $0.5 s. The high-resolution optical data from ASI enable us to pin down the ionospheric location of the preexisting arc and FAST measurements provide the properties of the precipitating particles that cause the auroral emissions.…”

Section: Data and Event Selectionmentioning

confidence: 99%

In situ observations of the “preexisting auroral arc” by THEMIS all sky imagers and the FAST spacecraft

Jiang¹,

Strangeway²,

Kivelson³

et al. 2012

J. Geophys. Res.

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[1] Auroral substorms were first described more than 40 years ago, and their atmospheric and magnetospheric signatures have been investigated extensively. However, because magnetic mapping from the ionosphere to the equator is uncertain especially during active times, the magnetospheric source regions of the substorm-associated features in the upper atmosphere remain poorly understood. In optical images, auroral substorms always involve brightening followed by poleward expansion of a discrete auroral arc. The arc that brightens is usually the most equatorward of several auroral arcs that remain quiescent for $30 min or more before the break-up commences. In order to identify the magnetospheric region that is magnetically conjugate to this preexisting arc, we combine auroral images from ground-based imagers, magnetic field and particle data from low-altitude spacecraft, and maps of field-aligned currents based on ground magnetometer arrays. We surveyed data from the THEMIS all sky imager (ASI) array and the FAST spacecraft from 2007 to April 2009 and obtained 5 events in which the low altitude FAST spacecraft crossed magnetic flux tubes linked to a preexisting auroral arc imaged by THEMIS ASI prior to substorm onset. The observations show that, in each of the five cases: 1) the precipitating electrons associated with the preexisting arc are accelerated by a field-aligned potential drop, with characteristic energy ranging from a few hundred eV to a few keV. 2) The preexisting arc is located 1 $2 poleward of the equatorward edge of the 1 keV electron plasma sheet in the ionosphere, and it maps to equatorial locations within the electron plasma sheet and tailward of its inner edge.3) The preexisting arc is located at or very near the boundary between the Region 1 and Region 2 field-aligned currents. The localization relative to the Region 1/Region 2 current is confirmed by comparison with maps of field-aligned currents inferred from ground magnetometer data.Citation: Jiang, F., R. J. Strangeway, M. G. Kivelson, J. M. Weygand, R. J. Walker, K. K. Khurana, Y. Nishimura, V. Angelopoulos, and E. Donovan (2012), In situ observations of the "preexisting auroral arc" by THEMIS all sky imagers and the FAST spacecraft,

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Section: Data and Event Selectionmentioning

confidence: 99%

In situ observations of the “preexisting auroral arc” by THEMIS all sky imagers and the FAST spacecraft

Jiang¹,

Strangeway²,

Kivelson³

et al. 2012

J. Geophys. Res.

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“…Maggs (1976) was the first to explain the generation of whistler mode auroral hiss by a coherent beam-plasma instability at the Landau resonance velocity. Numerous studies, including a statistical study using data from the Fast Auroral SnapshoT Explorer (FAST) (Pfaff et al, 2001), have shown that the majority of auroral hiss emissions are generated in the auroral downward current regions by low-energy upwardmoving electron beams (inverted-Vs) accelerated by downward parallel electric fields (Ergun et al, 2003). It should be noted that the inverted-Vs observed by FAST showed that the electrons can be broad in pitch angle but have peaked energy distributions.…”

Section: Introductionmentioning

confidence: 99%

The Generation of Upward‐Propagating Whistler Mode Waves by Electron Beams in the Jovian Polar Regions

et al. 2020

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Upward‐moving energetic electrons with energies of 1 MeV and above were observed over the entire Jovian polar region. The electrons were found to be associated with intense broadband whistler mode waves, similar to terrestrial whistler mode auroral hiss. Upward‐propagating whistler mode hiss at Earth is known to be generated by upward‐moving, magnetic field‐aligned electron beams (from electric field‐aligned potentials), by a beam‐plasma instability at the Landau resonance. Assuming this process at Jupiter, we present a linear stability analysis, showing the electron distribution functions (based on inverted‐V observations made by the Juno Jovian Auroral Distributions Experiment, JADE‐E, instrument) are unstable. The polarization of the modeled waves is consistent with whistler mode hiss (right‐hand circularly polarized). From the results of the linear stability analysis, we find that the calculated growth rates are sufficient to produce the observed whistler mode waves.

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“…[4] Recently, strong evidence that field-aligned electron beams generate terrestrial auroral hiss has been obtained by the Fast Auroral SnapshoT Explorer (FAST) [Pfaff et al, 2001]. The FAST satellite carries a high-resolution plasma instrument, and has shown that roughly 85% of auroral hiss emissions are generated by intense, low-energy, upwardpropagating electrons in the downward current region of the aurora [Ergun et al, 2003].…”

Section: Introductionmentioning

confidence: 99%

Electron beams as the source of whistler‐mode auroral hiss at Saturn

Kopf

Gurnett

Menietti

et al. 2010

Geophysical Research Letters

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Over the last three years, the Cassini spacecraft has been in a series of high inclination orbits, allowing investigation and measurements of Saturnian auroral phenomena. During this time, the Radio and Plasma Wave Science (RPWS) Investigation on Cassini detected low frequency whistler mode emissions propagating upward along the auroral field lines, much like terrestrial auroral hiss. Comparisons of RPWS data with Cassini Plasma Spectrometer (CAPS) plasma measurements during a high‐latitude pass on 17 October 2008, show that intense upward moving electron beams with energies of a few hundred eV were associated with auroral hiss emissions. In this paper we show that these beams produce large growth rates for whistler‐mode waves propagating along the resonance cone, similar to the generation of auroral hiss at Earth.

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Cited by 27 publications

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In situ observations of the “preexisting auroral arc” by THEMIS all sky imagers and the FAST spacecraft

In situ observations of the “preexisting auroral arc” by THEMIS all sky imagers and the FAST spacecraft

The Generation of Upward‐Propagating Whistler Mode Waves by Electron Beams in the Jovian Polar Regions

Electron beams as the source of whistler‐mode auroral hiss at Saturn

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