Magnetospheric electron density long‐term (&gt;1 day) refilling rates inferred from passive radio emissions measured by IMAGE RPI during geomagnetically quiet times

Denton, R. E.; Wang, Y.; Webb, P. A.; Tengdin, P. M.; Goldstein, J.; Redfern, J.; Reinisch, B. W.

doi:10.1029/2011ja017274

Cited by 45 publications

(77 citation statements)

References 39 publications

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“…Both SAMI3 and RAM‐CPL generally agree with measured refilling rates to within a factor of 2, and are often much closer. Given the degree of scatter in previous refilling measurements [see Denton et al , , Figure 1], this seems like a reasonable result. However, it should eventually be possible to obtain better agreement for a specific well‐measured event.…”

Section: Discussionsupporting

confidence: 71%

“…An extensive study by Denton et al [], using IMAGE/RPI plasmasphere density measurements during 2001–2006, provides context for the present work. Specifically, Denton et al [, Figure 1] found refilling rates lower than those reported from numerous previous measurements. We hypothesize that, prior to the IMAGE mission, reported measurements of individual events focused on cases where refilling was clearly evident.…”

Section: Discussionmentioning

confidence: 99%

“…Included are conjunctions with

{(Δ t_{UT}^{2} + Δ T_{MLT}^{2})}^{1 / 2} < 3

h and with IMAGE close to the magnetic equator (MLat <15°). For each conjunction, RPI electron densities from an IMAGE pass are interpolated to the specified L value and extrapolated to the magnetic equator [see Denton et al , , equation (5)].…”

Section: Plasmasphere Observationsmentioning

confidence: 99%

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Measurement and modeling of the refilling plasmasphere during 2001

et al. 2016

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The Naval Research Laboratory SAMI3 (Sami3 is Also a Model of the Ionosphere) and the RAM‐CPL (Ring current Atmosphere interaction Model‐Cold PLasma) codes are used to model observed plasmasphere dynamics during 25 November 2001 to 1 December 2001 and 1–5 February 2001. Model results compare well to plasmasphere observations of electron and mass densities. Comparison of model results to refilling data and to each other shows good agreement, generally within a factor of 2. We find that SAMI3 plasmaspheric refilling rates and ion densities are sensitive to the composition and temperature of the thermosphere and exosphere, and to photoelectron heating. Results also support our previous finding that the wind‐driven dynamo significantly impacts both refilling rates and plasmasphere dynamics during quiet periods.

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Section: Discussionsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 99%

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Measurement and modeling of the refilling plasmasphere during 2001

et al. 2016

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“…Finally a database of about 205,000 electron density measurements was created for this time period. Detailed information about the RPI data can be found in Webb et al (2007) and Denton et al (2012) and at http://ulcar.uml.edu/ rpi.html.…”

Section: Image Rpi Datamentioning

confidence: 99%

Validation of plasmasphere electron density reconstructions derived from data on board CHAMP by IMAGE/RPI data

Gerzen

Feltens

Jakowski

et al. 2015

Advances in Space Research

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Plasmaspheric electron content is, beyond the ionosphere as major source, a significant contributor to the overall TEC budget affecting GNSS signals. The plasmasphere can induce half or more of the GNSS range errors caused by atmospheric electrical charges, in particular at nighttime. At DLR Neustrelitz, Germany, GPS measurements recorded onboard the LEO satellite CHAMP were used to reconstruct the topside electron density distribution (ionosphere and plasmasphere) up to GPS altitude, applying a model-based assimilation technique. In this paper, the potential of these CHAMP topside reconstructions for analyzing space weather related changes in the geo-plasma is investigated. For this purpose, comparisons are made between the CHAMP reconstructed profiles and electron densities derived from passive radio wave observations by the IMAGE RPI instrument for years 2001 till 2005.The comparison results indicate that an improvement, compared to the electron density of a background model, can be achieved by CHAMP data assimilation. The improvement is especially visible in the L-shell region below 3, which contributes notably to the GNSS signal delays. However, for the region around the plasmapause, systematical electron density underestimations of the background model w.r.t. the IMAGE data are detected. The rather limited CHAMP data coverage and the degraded observation geometry at these high altitudes seem to be not sufficient for complete compensation of this underestimation during the assimilation procedure.The results presented in this paper demonstrate the strengths of LEO TEC data assimilation, but at the same time illustrate the necessity to improve the modeling of the plasmasphere region above 4 ER L-shell distances. Furthermore, they reveal the need of additional data to establish an appropriate data base for the modeling of the complete plasmasphere.

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“…If geomagnetic conditions become very quiet, cold plasma may corotate with the Earth at geostationary orbit even at other local time values so that the region of closed drift paths in Figure a may expand to enclose much or even all of geostationary orbit. In this case, long‐term refilling will occur [ Singh and Horwitz , ; Lemaire and Gringauz , ; Denton et al , ]. When the corotation region (region of closed drift paths) shrinks due to increased convection, the flow of relatively cold plasma from previously closed drift paths may stagnate in the afternoon (close to the point “S” in Figure b) and then flow sunward, leading to a high‐density plasmaspheric plume in the afternoon local time sector (path marked “Plume” in Figure b).…”

Section: Introductionmentioning

confidence: 99%

Evolution of mass density and O+ concentration at geostationary orbit during storm and quiet events

et al. 2014

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We investigated mass density ρm and O+ concentration ηO+≡nO+/ne (where nO+ and ne are the O+ and electron density, respectively) during two events, one active and one more quiet. We found ρm from observations of Alfvén wave frequencies measured by the GOES, and we investigated composition by combining measurements of ρm with measurements of ion density nMPA,i from the Magnetospheric Plasma Analyzer (MPA) instrument on Los Alamos National Laboratory spacecraft or ne from the Radio Plasma Imager instrument on the Imager for Magnetopause‐to‐Aurora Global Exploration spacecraft. Using a simple assumption for the He+ density at solar maximum based on a statistical study, we found ηO+ values ranging from near zero to close to unity. For geostationary spacecraft that corotate with the Earth, sudden changes in density for both ρm and ne often appear between dusk and midnight magnetic local time, especially when Kp is significantly above zero. This probably indicates that the bulk (total) ions have energy below a few keV and that the satellites are crossing from closed or previously closed to open drift paths. During long periods that are geomagnetically quiet, the mass density varies little, but ne gradually refills leading to a gradual change in composition from low‐density plasma that is relatively cold and heavy (high‐average ion mass M ≡ ρm/ne) to high‐density plasma that is relatively cold and light (low M) plasmasphere‐like plasma. During active periods we observe a similar daily oscillation in plasma properties from the dayside to the nightside, with cold and light high‐density plasma (more plasmasphere‐like) on the dayside and hotter and more heavy low‐density plasma (more plasma sheet‐like) on the nightside. The value of ne is very dependent on whether it is measured inside or outside a plasmaspheric plume, while ρm is not. All of our results were found at solar maximum; previous results suggest that there will be much less O+ at solar minimum under all conditions.

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Magnetospheric electron density long‐term (>1 day) refilling rates inferred from passive radio emissions measured by IMAGE RPI during geomagnetically quiet times

Cited by 45 publications

References 39 publications

Measurement and modeling of the refilling plasmasphere during 2001

Measurement and modeling of the refilling plasmasphere during 2001

Validation of plasmasphere electron density reconstructions derived from data on board CHAMP by IMAGE/RPI data

Evolution of mass density and O+ concentration at geostationary orbit during storm and quiet events

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