The local-time variation of the quiet plasmasphere: geosynchronous observations and kinetic theory

Reynolds, M. A.; Ganguli, G.; Su, Y-J; Thomsen, M. F.

doi:10.5194/angeo-21-2147-2003

Cited by 8 publications

(7 citation statements)

References 24 publications

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“…Over long-term intervals, the ionospheric source linked to a magnetic flux tube in co-rotation is switched off in the night sector, which increases the overall refilling duration. The consequence of the equatorial drift pattern on the refilling process is clearly illustrated by daily variations of the quiet plasmasphere density observed from the geosynchronous orbit (Reynolds et al, 2003). One can note that the dayside outer plasmasphere region is under replenishment quasi-permanently, whatever the fate of flux tubes when they reach the afternoon sector, co-rotation or sunward convection drift (Décréau et al, 1982).…”

Section: Magnetic Field Coordinate Systemmentioning

confidence: 95%

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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Section: Magnetic Field Coordinate Systemmentioning

confidence: 95%

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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“…More recent observations found significant refilling in less than 28 hours near R = 2.5 R E ), but still insufficient to reach saturation levels. Reynolds et al (2003) compared locally measured plasma densities with theoretical predictions obtained from a multispecies kinetic model. The observed density level was at most only 25% of saturation density, and the density still appeared to increase even after three days of very quiet geomagnetic activity.…”

Section: The Quiet Plasmaspherementioning

confidence: 98%

“…Such periods are most likely to exist during solar minimum. Reynolds et al (2003) recently listed the yearly The red line is the electron gyrofrequency determined from the Tsyganenko and Stern (1996) model. The gray strips indicate frequencies and times when no passive data were measured from RPI.…”

Section: The Quiet Plasmaspherementioning

confidence: 99%

Plasmaspheric Density Structures and Dynamics: Properties Observed by the CLUSTER and IMAGE Missions

et al. 2008

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Plasmaspheric density structures have been studied since the discovery of the plasmasphere in the late 1950s. But the advent of the CLUSTER and IMAGE missions in 2000 has added substantially to our knowledge of density structures, thanks to the new 56 F. Darrouzet et al.capabilities of those missions: global imaging with IMAGE and four-point in situ measurements with CLUSTER. The study of plasma sources and losses has given new results on refilling rates and erosion processes. Two-dimensional density images of the plasmasphere have been obtained. The spatial gradient of plasmaspheric density has been computed. The ratios between H + , He + and O + have been deduced from different ion measurements. Plasmaspheric plumes have been studied in detail with new tools, which provide information on their morphology, dynamics and occurrence. Density structures at smaller scales have been revealed with those missions, structures that could not be clearly distinguished before the global images from IMAGE and the four-point measurements by CLUSTER became available. New terms have been given to these structures, like "shoulders", "channels", "fingers" and "crenulations". This paper reviews the most relevant new results about the plasmaspheric plasma obtained since the start of the CLUSTER and IMAGE missions.

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“…The hydrogen ion and helium ion density in the equatorial plane are found to exhibit local-time variations that are sensitive to the details of the exobase conditions and the diurnal convection. The theoretical predictions of the kinetic model were also compared with the quiet-time structure of the plasmaspheric density investigated using observations of the LANL geosynchronous satellites (Reynolds et al 2003).…”

Section: Other Models Of the Plasmaspherementioning

confidence: 99%

Recent Progress in Physics-Based Models of the Plasmasphere

et al. 2009

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We describe recent progress in physics-based models of the plasmasphere using the fluid and the kinetic approaches. Global modeling of the dynamics and influence of the plasmasphere is presented. Results from global plasmasphere simulations are used to understand and quantify (i) the electric potential pattern and evolution during geomagnetic storms, and (ii) the influence of the plasmasphere on the excitation of electromagnetic ion cyclotron (EMIC) waves and precipitation of energetic ions in the inner magnetosphere. The interactions of the plasmasphere with the ionosphere and the other regions of the magnetosphere are pointed out. We show the results of simulations for the formation of the plasmapause and discuss the influence of plasmaspheric wind and of ultra low frequency (ULF) waves for transport of plasmaspheric material. Theoretical models used to describe the electric field and plasma distribution in the plasmasphere are presented. Model predictions are compared to recent CLUSTER and IMAGE observations, but also to results of earlier models and satellite observations.

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The local-time variation of the quiet plasmasphere: geosynchronous observations and kinetic theory

Cited by 8 publications

References 24 publications

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

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

Plasmaspheric Density Structures and Dynamics: Properties Observed by the CLUSTER and IMAGE Missions

Recent Progress in Physics-Based Models of the Plasmasphere

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