FAST satellite wave observations in the AKR source region

Ergun, R. E.; Carlson, C. W.; McFadden, J. P.; Mozer, F. S.; Delory, G. T.; Peria, W. J.; Chaston, C. C.; Temerin, M.; Elphic, R. C.; Strangeway, R. J.; Pfaff, R. F.; Cattell, C. A.; Klumpar, D. M.; Shelley, E. G.; Peterson, W. K.; Möbius, E.; Kistler, L. M.

doi:10.1029/98gl00570

Cited by 188 publications

(169 citation statements)

References 14 publications

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“…Based on these results, it is now believed that auroral kilometric radiation is generated by a mechanism known as the cyclotron maser (Wu and Lee, 1979). In this mechanism, electrons are quasitrapped by the magnetic mirror force and the electric field (Louarn et al, 1990;Roux et al, 1993;Ergun et al, 1998;Delory et al, 1998). The cyclotron maser mechanism is also believed to be responsible for the intense radio emissions that have been observed from Jupiter, Saturn, Uranus, and Nep-tune.…”

Section: Auroral Kilometric Radiationmentioning

confidence: 99%

First results from the Cluster wideband plasma wave investigation

et al. 2001

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Abstract. In this report we present the first results from the Cluster wideband plasma wave investigation. The four Cluster spacecraft were successfully placed in closely spaced, high-inclination eccentric orbits around the Earth during two separate launches in July -August 2000. Each spacecraft includes a wideband plasma wave instrument designed to provide high-resolution electric and magnetic field waveforms via both stored data and direct downlinks to the NASA Deep Space Network. Results are presented for three commonly occurring magnetospheric plasma wave phenomena: (1) whistlers, (2) chorus, and (3) auroral kilometric radiation. Lightning-generated whistlers are frequently observed when the spacecraft is inside the plasmasphere. Usually the same whistler can be detected by all spacecraft, indicating that the whistler wave packet extends over a spatial dimension at least as large as the separation distances transverse to the magnetic field, which during these observations were a few hundred km. This is what would be expected for nonducted whistler propagation. No case has been found in which a strong whistler was detected at one spacecraft, with no signal at the other spacecraft, which would indicate ducted propagation. Whistler-mode chorus emissions are also observed in the inner region of the magnetosphere. In contrast to lightninggenerated whistlers, the individual chorus elements seldom show a one-to-one correspondence between the spacecraft, indicating that a typical chorus wave packet has dimensions transverse to the magnetic field of only a few hundred km or less. In one case where a good one-to-one correspondence existed, significant frequency variations were observed between the spacecraft, indicating that the frequency of the wave packet may be evolving as the wave propagates. Auroral kilometric radiation, which is an intense radio emission generated along the auroral field lines, is frequently observed over the polar regions. The frequency-time structure of this radiation usually shows a very good one-to-one correspondence between the various spacecraft. By using the Correspondence to: D. A. Gurnett (donald-gurnett@uiowa.edu) microsecond timing available at the NASA Deep Space Network, very-long-baseline radio astronomy techniques have been used to determine the source of the auroral kilometric radiation. One event analyzed using this technique shows a very good correspondence between the inferred source location, which is assumed to be at the electron cyclotron frequency, and a bright spot in the aurora along the magnetic field line through the source.

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Section: Auroral Kilometric Radiationmentioning

confidence: 99%

First results from the Cluster wideband plasma wave investigation

et al. 2001

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“…In this context, a large number of investigations have been made to study the characteristics of IAWs in two-temperature electron plasmas [5][6][7][8][9]. Such two-temperature plasmas have been observed by various satellite missions, e.g., Fast Auroral Snapshot (FAST) at the auroral region [10], Viking Satellite [4] and THEMIS mission [11]. Furthermore, several investigations made by GEOTAIL and POLAR [12] in the magnetosphere have also confirmed the existence of such electron populations.…”

Section: Introductionmentioning

confidence: 99%

Modulation of ion-acoustic waves in a nonextensive plasma with two-temperature electrons

2015

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We study the amplitude modulation of ion-acoustic wave (IAW) packets in an unmagnetized electron-ion plasma with two-temperature (cool and hot) electrons in the context of the Tsallis' nonextensive statistics. Using the multiple-scale technique, a nonlinear Schrödinger (NLS) equation is derived which governs the dynamics of modulated wave packets. It is shown that in nonextensive plasmas, the IAW envelope is always stable for long-wavelength modes (k → 0) and unstable for short-wavelengths with k > ∼ 1. However, the envelope can be unstable at an intermediate scale of perturbations with 0 < k < 1. Thus, the modulated IAW packets can propagate in the form of bright envelope solitons or rogons (at small-and medium scale perturbations) as well as dark envelope solitons (at large scale). The stable and unstable regions are obtained for different values of temperature and density ratios as well as the nonextensive parameters qc and q h for cool and hot electrons. It is found that the more (less) the population of superthermal cool (hot) electrons, the smaller is the growth rate of instability with cutoffs at smaller wave numbers of modulation.

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“…Furthermore, the range of the AKR source can be roughly regarded as equivalent to that of the acceleration region because AKR is the result of wave-particle interaction with electron beams in the acceleration region (e.g. Ergun et al, 1998;Pottelette et al, 2001). not always common and several terms have been used to depict auroral substorms (Rostoker et al, 1980), such as "initial brightening", "intensification", "brightening", "poleward expansion", "expansion onset", "expansive phase onset", and "full onset", partly because auroral substorms include several steps to complete the onset process and manifest various evolutions.…”

Section: Introductionmentioning

confidence: 99%

Vertical evolution of auroral acceleration at substorm onset

et al. 2009

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Abstract. This study describes the onset process of auroral substorms in connection with the vertical evolution of auroral particle acceleration, on the basis of auroral kilometric radiation (AKR) dynamics. We show that the auroral acceleration process at substorm onset basically consists of two stages: (1) appearance/intensification of a low-altitude acceleration region at 4000-5000 km accompanied by initial brightening and (2) breakout of high-altitude field-aligned acceleration above the pre-existing low-altitude acceleration region at 6000-12 000 km, which is followed by auroral breakup and poleward expansion. It is also revealed that this two-stage evolution of auroral acceleration corresponds to the two-step reinforcement of field-aligned current.

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FAST satellite wave observations in the AKR source region

Cited by 188 publications

References 14 publications

First results from the Cluster wideband plasma wave investigation

First results from the Cluster wideband plasma wave investigation

Modulation of ion-acoustic waves in a nonextensive plasma with two-temperature electrons

Vertical evolution of auroral acceleration at substorm onset

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