Plasma density distribution along the magnetospheric field: RPI observations from IMAGE

Reinisch, B. W.; Huang, Xueqin; Song, P.; Sales, Gary S.; Fung, S. F.; Green, J. L.; Gallagher, D. L.; Vasyliūnas, V. M.

doi:10.1029/2001gl013684

Cited by 94 publications

(127 citation statements)

References 19 publications

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“…1.12. This mode-coupling interpretation of Reinisch et al [61], involving the Z-mode to explain the weaker companion echoes to the inter-hemisphere magnetospheric RPI X-mode echoes, differs from the interpretation of Muldrew [48] of inter-hemisphere ionospheric echoes observed by Alouette 1 in that Muldrew [48] did not invoke O-Z-O mode coupling.…”

Section: Remote O-z-o-mode Couplingcontrasting

confidence: 45%

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Active Wave Experiments in Space Plasmas: The Z Mode

Benson

Webb

Green

et al.

Geospace Electromagnetic Waves and Radiation

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Abstract. The term Z mode is space physics notation for the low-frequency branch of the extraordinary (X) mode. It is an internal, or trapped, mode of the plasma confined in frequency between the cutoff frequency fz and the upper-hybrid frequency f uh which is related to the electron plasma frequency fpe and the electron cyclotron frequency fce by the expression f; fz is a function of fpe and fce. These characteristic frequencies are directly related to the electron number density Ne and the magnetic field strength |B|, i.e., fpe (kHz) 2 ≈ 80.6Ne(cm −3 ) and fce (kHz) 2 ≈ 0.028|B|(nT). The Z mode is further classified as slow or fast depending on whether the phase velocity is lower or higher than the speed of light in vacuum. The Z mode provides a link between the short wavelength λ (large wave number k = 2π/λ ) electrostatic (es) domain and the long λ (small k) electromagnetic (em) domain. An understanding of the generation, propagation and reception of Z-mode waves in space plasma leads to fundamental information on wave/particle interactions, Ne, and field-aligned Ne irregularities (FAI) in both active and passive wave experiments. Here we review Z-mode observations and their interpretations from both radio sounders on rockets and satellites and from plasma-wave receivers on satellites. The emphasis will be on the scattering and ducting of sounder-generated Z-mode waves by FAI and on the passive reception of Z-mode waves generated by natural processes such as Cherenkov and cyclotron emission. The diagnostic applications of the observations to understanding ionospheric and magnetospheric plasma processes and structures benefit from the complementary nature of passive and active plasma-wave experiments.

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Section: Remote O-z-o-mode Couplingcontrasting

confidence: 45%

“…1.7, were identified by Fung et al [26]; an example where the Z mode played a prominent role in the interpretation is shown in Fig. 1.12 from Reinisch et al [61]. This record is called a plasmagram and is the magnetospheric analog of the ionospheric topside-sounder ionogram examples shown in Figs.…”

Section: Remote O-z-o-mode Couplingmentioning

confidence: 99%

Active Wave Experiments in Space Plasmas: The Z Mode

Benson

Webb

Green

et al.

Geospace Electromagnetic Waves and Radiation

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“…The error margins are large away from perigee as both B and ∇|B| are small there. Angle α B,∇n e remains quite large throughout the time interval, indicating that ∇ || n e ∇ ⊥ n e at the relatively low latitudes Cluster is sampling, something that has also been found with radio sounding techniques (Reinisch et al, 2001). This is due to a small longitudinal gradient within each flux tube, but also because of the existence of strong radial and azimuthal density structure on the transverse homogeneity scale of 500 km adopted here.…”

Section: Physical Relevancementioning

confidence: 69%

Least-squares gradient calculation from multi-point observations of scalar and vector fields: methodology and applications with Cluster in the plasmasphere

et al. 2007

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Abstract. This paper describes a general-purpose algorithm for computing the gradients in space and time of a scalar field, a vector field, or a divergence-free vector field, from in situ measurements by one or more spacecraft. The algorithm provides total error estimates on the computed gradient, including the effects of measurement errors, the errors due to a lack of spatio-temporal homogeneity, and errors due to small-scale fluctuations. It also has the ability to diagnose the conditioning of the problem. Optimal use is made of the data, in terms of exploiting the maximum amount of information relative to the uncertainty on the data, by solving the problem in a weighted least-squares sense. The method is illustrated using Cluster magnetic field and electron density data to compute various gradients during a traversal of the inner magnetosphere. In particular, Cluster is shown to cross azimuthal density structure, and the existence of field-aligned currents in the plasmasphere is demonstrated.

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“…Tu et al (2006) extended the technique used by Reinisch et al (2001Reinisch et al ( , 2004 and Huang et al (2004) to model the field-aligned electron density profile remotely from the Radio Plasma Imager (RPI) on board the IMAGE satellite. They concluded that the power law dependence quoted above is reliable enough to construct global empirical plasmasphere/trough models.…”

Section: G Lointier Et Al: Refilling Process In the Plasmaspherementioning

confidence: 99%

Refilling process in the plasmasphere: a 3-D statistical characterization based on Cluster density observations

Lointier¹,

Darrouzet

Décréau³

et al. 2013

Ann. Geophys.

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Abstract. The Cluster mission offers an excellent opportunity to investigate the evolution of the plasma population in a large part of the inner magnetosphere, explored near its orbit's perigee, over a complete solar cycle. The WHISPER sounder, on board each satellite of the mission, is particularly suitable to study the electron density in this region, between 0.2 and 80 cm−3. Compiling WHISPER observations during 1339 perigee passes distributed over more than three years of the Cluster mission, we present first results of a statistical analysis dedicated to the study of the electron density morphology and dynamics along and across magnetic field lines between L = 2 and L = 10. In this study, we examine a specific topic: the refilling of the plasmasphere and trough regions during extended periods of quiet magnetic conditions. To do so, we survey the evolution of the ap index during the days preceding each perigee crossing and sort out electron density profiles along the orbit according to three classes, namely after respectively less than 2 days, between 2 and 4 days, and more than 4 days of quiet magnetic conditions (ap ≤ 15 nT) following an active episode (ap > 15 nT). This leads to three independent data subsets. Comparisons between density distributions in the 3-D plasmasphere and trough regions at the three stages of quiet magnetosphere provide novel views about the distribution of matter inside the inner magnetosphere during several days of low activity. Clear signatures of a refilling process inside an expended plasmasphere in formation are noted. A plasmapause-like boundary, at L ~ 6 for all MLT sectors, is formed after 3 to 4 days and expends somewhat further after that. In the outer part of the plasmasphere (L ~ 8), latitudinal profiles of median density values vary essentially according to the MLT sector considered rather than according to the refilling duration. The shape of these density profiles indicates that magnetic flux tubes are not fully replenished after 6 days of quiet conditions. In addition, the outer plasmasphere in the night and dawn sectors (22:00 to 10:00 MLT range) maintains an overall clear deficit of ionospheric population, when compared to the situation in the noon and dusk sectors (10:00 to 22:00 MLT range).

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Plasma density distribution along the magnetospheric field: RPI observations from IMAGE

Cited by 94 publications

References 19 publications

Active Wave Experiments in Space Plasmas: The Z Mode

Active Wave Experiments in Space Plasmas: The Z Mode

Least-squares gradient calculation from multi-point observations of scalar and vector fields: methodology and applications with Cluster in the plasmasphere

Refilling process in the plasmasphere: a 3-D statistical characterization based on Cluster density observations

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