Electromagnetic instabilities in the plasma sheet boundary layer

Angelopoulos, V.; Elphic, R. C.; Gary, S. Peter; Huang, C. Y.

doi:10.1029/ja094ia11p15373

Cited by 35 publications

(46 citation statements)

References 34 publications

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“…(1) for the parameters indicated in Table 1 calculated in the satellites' frame ofreference. For each value ofkc/wp there exists three roots in w/S2p each ofwhich correspond closely to the roots obtained by Angelopoulos et al (1989). However, since the form of the ion distribution differs, the frequency, polarization, and growth rate for these roots are shifted such that positive growth rates for left-handed waves below f2p occur.…”

Section: Modellingsupporting

confidence: 71%

“…At shorter wavelengths a second growing mode occurs (w3, y3) over wave numbers kc/wp -0.6-1.2 for left-hand waves at frequencies w/fZp -1.2-1.5flp. This doppler-shifted mode is identified by Angelopoulos et al (1989) as another branch of the ion cyclotron anisotropy instability, driven unstable by the anisotropy of the earthward or parallel travelling beam . However, our results indicate that the growth of this mode is dependent upon the temperature and density of the anti-parallel beam and not necessarily the anisotropy of the parallel earthward directed beam.…”

Section: Modellingmentioning

confidence: 99%

“…Similarly, in the plasma sheet boundary layer ion distributions are anisotropic and energetic, however they are typically dominated by field-aligned counterstreaming proton beams with energies from 0.5 to >20 keV (Eastman et al, 1984). Distributions with these characteristics are favourable for the growth of several electrostatic and electromagnetic instabilities, including the anisotropic ion cyclotron instability (Akimoto and Omidi, 1986;Angelopoulos et al, 1989;Gary and Winske, 1990;Winske and Omidi, 1992). While electrostatic waves in this region have received considerable attention, electromagnetic fluctuations particularly in the vicinity of the H+ cyclotron frequency, remain largely unstudied.…”

Section: Introductionmentioning

confidence: 99%

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Electromagnetic Ion Cyclotron Waves Observed in the Near Earth Plasma Sheet Boundary Layer.

Chaston¹,

Hu²,

Fraser³

et al. 1994

J. geomagn. geoelec

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Enhanced magnetic field fluctuations observed during an ISEE-2 crossing of the plasma sheet boundary layer at XGSE = 18.2 Re have the characteristics of electromagnetic ion cyclotron waves. The observed fluctuations propagate essentially along the magnetic field and are left-hand circularly polarized in the spacecraft frame, with frequencies below the proton cyclotron frequency (S2p) and peak power at about 0.2S2p. Plasma data indicate that these waves are associated with decreasing plasma j3 and occur in the presence of an anisotropic earthward directed proton beam with velocity less than the local Alfven speed. Linear Vlasov theory indicates that these waves are most likely excited by the electromagnetic ion cyclotron instability driven by the temperature anisotropy of the proton beam.

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Section: Modellingsupporting

confidence: 71%

Section: Modellingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Electromagnetic Ion Cyclotron Waves Observed in the Near Earth Plasma Sheet Boundary Layer.

Chaston¹,

Hu²,

Fraser³

et al. 1994

J. geomagn. geoelec

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“…The typical phase velocity of these fluctuations is of the order of local Alfvén velocity, which is more than twice below the measured ion flow speed in the most cases considered in our study. The generation of this type of oscillations can be caused by a development of the currentdriven kink-like instability (Angelopoulos et al, 1989;Gary and Winske, 1990) or the Kelvin-Helmholtz (KH) instability (Sauvaud et al, 2004). Since in the most part of the PSBL crossings analyzed in the present study the currents, corresponding to electron-ion relative drift, are very low (see Fig.…”

Section: Kelvin-helmholtz Instability In a Bounded Flowmentioning

confidence: 83%

Large-scale fluctuations of PSBL magnetic flux tubes induced by the field-aligned motion of highly accelerated ions

et al. 2010

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Abstract. We present a comprehensive analysis of magnetic field and plasma data measured in the course of 170 crossings of the lobeward edge of Plasma Sheet Boundary Layer (PSBL) in the Earth's magnetotail by Cluster spacecraft. We found that large-scale fluctuations of the magnetic flux tubes have been registered during intervals of propagation of high velocity field-aligned ions. The observed kink-like oscillations propagate earthward along the main magnetic field with phase velocities of the order of local Alfvén velocity and have typical wavelengths ∼5-20 R E , and frequencies of the order of 0.004-0.02 Hz. The oscillations of PSBL magnetic flux tubes are manifested also in a sudden increase of drift velocity of cold lobe ions streaming tailward. Since in the majority of PSBL crossings in our data set, the densities of currents corresponding to electron-ion relative drift have been low, the investigation of Kelvin-Helmholtz (K-H) instability in a bounded flow sandwiched between the plasma sheet and the lobe has been performed to analyze its relevance to generation of the observed ultra-low frequency oscillations with wavelengths much larger than the flow width. The calculations have shown that, when plasma conditions are favorable for the excitation of K-H instability at least at one of the flow boundaries, kink-like ultra-low frequency waves, resembling the experimentally observed ones, could become unstable and efficiently develop in the system.

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“…If the tailward ion beams are originating from reflection at the near-Earth region, the tailward ion beams have to overcome the pitch-angle scattering due to the ion beam instabilities (Angelopoulos et al, 1989). The travel time of the ion beam between the source region and the Earth, normalized by the ion cyclotron frequency, becomes 3)…”

Section: Discussionmentioning

confidence: 99%

Evidence of Two Active Reconnection Sites in the Distant Magnetotail

Hoshino¹,

Mukai²,

Nishida³

et al. 1996

J. geomagn. geoelec

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Prior to the observation of fast tailward plasma flows, earthward plasma flows are often observed in the distant magnetotail. By studying the evolution of the ion distribution functions for the transition flow from earthward to tailward flow, we find a multi-layer structure of beamlike plasma flows in the plasma sheet boundary layer, PSBL: 1) earthward, anisotropic beam plasma can be observed in the outer region of PSBL, i.e., the plasma lobe side of the PSBL; and 2) the counterstreaming ions, which consist of earthward and tailward beam-like plasma flows, are observed in the inner region of the PSBL; i.e., the plasma sheet side. Inside the plasma sheet, an isotropic, hot ion plasma can be observed. These characteristics are similar to those measured in the PSBL closer to the Earth, and the tailward anisotropic ion beams observed in the near-Earth magnetotail are thought to be the mirrored counterpart of the earthward ion beam. In the distant magnetotail, however, it is not easy to explain the tailward beam as the mirrored counterpart, because the reflected ion beams at the Earth will be absorbed into the plasma sheet before the reflected ions can travel to the distant magnetotail. We propose another model of two active magnetic reconnection sites. The tailward ion beams come from a near-Earth reconnection site which is embedded in the distant magnetotail reconnection site ejecting the earthward flow.

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Electromagnetic instabilities in the plasma sheet boundary layer

Cited by 35 publications

References 34 publications

Electromagnetic Ion Cyclotron Waves Observed in the Near Earth Plasma Sheet Boundary Layer.

Electromagnetic Ion Cyclotron Waves Observed in the Near Earth Plasma Sheet Boundary Layer.

Large-scale fluctuations of PSBL magnetic flux tubes induced by the field-aligned motion of highly accelerated ions

Evidence of Two Active Reconnection Sites in the Distant Magnetotail

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