Thermal ion composition measurements of the formation of the new outer plasmasphere and double plasmapause during storm recovery phase

Horwitz, J. L.; Comfort, R. H.; Chappell, C. R.

doi:10.1029/gl011i008p00701

Cited by 128 publications

(114 citation statements)

References 11 publications

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“…The plasma morphology of the event summarized by Figs. 8 and 9 is in agreement with the presence of a heavy ion ''torus'' or ''shell'' in the vicinity of the plasmapause (Horwitz et al 1984;Singh et al 1992;Fraser et al 2005) as the oxygen ion density significantly exceeds the proton density. Exactly how this affects ULF wave generation is not yet fully understood (Fraser et al 2005) but it is suggested to be possible at locations where the drift-bounce resonance frequency matches the eigenfrequency of local standing Alfvén waves.…”

Section: Ulf Waves In the Plasmasphere Boundary Layer And Related Ionsupporting

confidence: 65%

The interaction of ultra-low-frequency pc3-5 waves with charged particles in Earth’s magnetosphere

Zong

Rankin

Zhou

2017

Rev. Mod. Plasma Phys.

140

162

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One of the most important issues in space physics is to identify the dominant processes that transfer energy from the solar wind to energetic particle populations in Earth's inner magnetosphere. Ultra-low-frequency (ULF) waves are an important consideration as they propagate electromagnetic energy over vast distances with little dissipation and interact with charged particles via drift resonance and drift-bounce resonance. ULF waves also take part in magnetosphereionosphere coupling and thus play an essential role in regulating energy flow throughout the entire system. This review summarizes recent advances in the characterization of ULF Pc3-5 waves in different regions of the magnetosphere, including ion and electron acceleration associated with these waves.

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Section: Ulf Waves In the Plasmasphere Boundary Layer And Related Ionsupporting

confidence: 65%

The interaction of ultra-low-frequency pc3-5 waves with charged particles in Earth’s magnetosphere

Zong

Rankin

Zhou

2017

Rev. Mod. Plasma Phys.

140

162

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“…[26] The oxygen torus was first reported by Chappell [1982] and then investigated in subsequent studies of Horwitz et al [1984Horwitz et al [ , 1986, Roberts et al [1987], and Comfort et al [1988]. All of these previous studies utilized the DE-1/RIMS data.…”

Section: Comparison With De-1/rims Resultsmentioning

confidence: 99%

“…Chappell [1982] ions in the outer plasmasphere. This "oxygen torus" has been identified in subsequent studies using the DE-1/RIMS data [Horwitz et al, 1984[Horwitz et al, , 1986Roberts et al, 1987;Comfort et al, 1988]. Horwitz et al [1984Horwitz et al [ , 1986 showed that the O + and O 2+ densities become comparable to or exceeds the H + density at L = 3-4.…”

Section: Introductionmentioning

confidence: 99%

“…This "oxygen torus" has been identified in subsequent studies using the DE-1/RIMS data [Horwitz et al, 1984[Horwitz et al, , 1986Roberts et al, 1987;Comfort et al, 1988]. Horwitz et al [1984Horwitz et al [ , 1986 showed that the O + and O 2+ densities become comparable to or exceeds the H + density at L = 3-4. A statistical analysis of the oxygen torus (identified by O + and O 2+ ions) was made by Roberts et al [1987], who found that (1) the oxygen torus is observed just inside the plasmasphere at all local time with higher occurrence frequency in the late evening and morning sectors, (2) it is identified on ∼50% of orbits, (3) its occurrence frequency does not depend on the Kp index and is still fairly high even in the low Kp case (Kp = 0-2+), and (4) a density peak of the oxygen torus generally shifts toward lower L shell with increasing geomagnetic activity.…”

Section: Introductionmentioning

confidence: 99%

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Oxygen torus in the deep inner magnetosphere and its contribution to recurrent process of O⁺-rich ring current formation

et al. 2011

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[1] Using the magnetic field and plasma wave data obtained by the Combined Release and Radiation Effects Satellite (CRRES), we search for enhancements of O + ion density in the deep inner magnetosphere known as "the oxygen torus". We examine 4 events on the dayside in which toroidal standing Alfvén waves appear clearly. From the frequency of the toroidal waves, the magnetospheric local mass density (r L ) is estimated by solving the MHD wave equation for realistic models of the magnetic field and the field line mass distribution. We also estimate the local electron number density (n eL ) from the plasma wave spectrograms by identifying narrow-band emission at the upper-hybrid resonance frequency. Assuming the quasi-neutral condition of plasma, we infer the local average ion mass (M L ) by r L /n eL . It is found that M L is approximately 3 amu in the plasma trough, while it shows an enhancement of >7 amu at L ∼ 4.5-6.5 that is close to the plasmapause at L ∼ 3.5-6.0. This indicates an existence of the oxygen torus in the vicinity of the plasmapause. The oxygen torus is found preferentially during the storm recovery phase. We interpret that these features of the oxygen torus (i.e., close relations with the plasmapause and the storm recovery phase) reflect its generation mechanism; that is, the ionospheric temperature is enhanced by heat conduction from high altitudes in the limited L range where the plasmasphere, because of its inflation during the recovery phase, encounters the ring current, and then the ionosphere has a larger scale height and supplies O + ions to the inner magnetosphere, resulting in the oxygen torus. We also discuss the contribution of the oxygen torus to the formation of the O + -rich ring current. It is proposed that the O + -rich ring current is formed in a recurrent process, in which the oxygen torus, the plasmasphere, and the ring current interact with each other.

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“…Horwitz et al (1984) presented results from the DE-1 satellite data for the storm of 12-13 November 1981. After the time of maximum disturbance, He + is observed to rival H + as the dominant ion close to an L-shell of 3.5 and at an altitude between 1.5 and 2.8 R E .…”

Section: Introductionmentioning

confidence: 99%

He<sup>+</sup> dominance in the plasmasphere during geomagnetically disturbed periods: 1. Observational results

et al. 2002

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Abstract.Observations made by the DMSP F10 satellite during the recovery phase from geomagnetic disturbances in June 1991 show regions of He + dominance around 830 km altitude at 09:00 MLT. These regions are co-located with a trough in ionisation observed around 55 • in the winter hemisphere. Plasma temperature and concentration observations made during the severe geomagnetic storm of 24 March 1991 are used as a case study to determine the effects of geomagnetic disturbances along the orbit of the F10 satellite. Previous explanations for He + dominance in this trough region relate to the part of the respective flux tubes that is in darkness. Such conditions are not relevant for this study, since the whole of the respective flux tubes are sunlit. A new mechanism is proposed to explain the He + dominance in the trough region. This mechanism is based on plasma transport and chemical reaction effects in the F-region and topside ionosphere, and on the time scales for such chemical reactions. Flux tubes previously depleted by geomagnetic storm effects refill during the recovery phase from the ionosphere as a result of pressure differences along the flux tubes. Following a geomagnetic disturbance, the He + ion recovers quickly via the rapid photoionisation of neutral helium, in the F-region and the topside. The recovery of the O + and H + ions is less rapid. This is proposed as a result of the respective charge exchange reactions with neutral atomic hydrogen and oxygen. Preliminary model calculations support the proposed mechanism.

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Thermal ion composition measurements of the formation of the new outer plasmasphere and double plasmapause during storm recovery phase

Cited by 128 publications

References 11 publications

The interaction of ultra-low-frequency pc3-5 waves with charged particles in Earth’s magnetosphere

The interaction of ultra-low-frequency pc3-5 waves with charged particles in Earth’s magnetosphere

Oxygen torus in the deep inner magnetosphere and its contribution to recurrent process of O⁺-rich ring current formation

He<sup>+</sup> dominance in the plasmasphere during geomagnetically disturbed periods: 1. Observational results

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Thermal ion composition measurements of the formation of the new outer plasmasphere and double plasmapause during storm recovery phase

Cited by 128 publications

References 11 publications

The interaction of ultra-low-frequency pc3-5 waves with charged particles in Earth’s magnetosphere

The interaction of ultra-low-frequency pc3-5 waves with charged particles in Earth’s magnetosphere

Oxygen torus in the deep inner magnetosphere and its contribution to recurrent process of O+-rich ring current formation

He&lt;sup&gt;+&lt;/sup&gt; dominance in the plasmasphere during geomagnetically disturbed periods: 1. Observational results

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Oxygen torus in the deep inner magnetosphere and its contribution to recurrent process of O⁺-rich ring current formation

He<sup>+</sup> dominance in the plasmasphere during geomagnetically disturbed periods: 1. Observational results