The fate of the outer plasmasphere

Elphic, R. C.; Thomsen, M. F.; Borovsky, Joseph E.

doi:10.1029/97gl00141

Cited by 74 publications

(57 citation statements)

References 19 publications

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“…Cold plasma originating from plasmaspheric detachments have been reported in the magnetosphere in several studies (e.g. Chappell, 1974;Elphic et al, 1996;Matsui et al, 1999;Foster et al, 2004), mainly on the dayside, but it may also propagate to the tail (Elphic et al, 1997). Of particular interest are the reports from Cluster and Polar (Chen and Moore, 2004) on cold plasmas with density ∼1 cm −3 and temperature below 10 eV just inside the magnetopause.…”

Section: Implications For Other Regionsmentioning

confidence: 99%

Electric field measurements on Cluster: comparing the double-probe and electron drift techniques

et al. 2006

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Abstract. The four Cluster satellites each carry two instruments designed for measuring the electric field: a doubleprobe instrument (EFW) and an electron drift instrument (EDI). We compare data from the two instruments in a representative sample of plasma regions. The complementary merits and weaknesses of the two techniques are illustrated. EDI operations are confined to regions of magnetic fields above 30 nT and where wave activity and keV electron fluxes are not too high, while EFW can provide data everywhere, and can go far higher in sampling frequency than EDI. On the other hand, the EDI technique is immune to variations in the low energy plasma, while EFW sometimes detects significant nongeophysical electric fields, particularly in regions with drifting plasma, with ion energy (in eV) below the spacecraft potential (in volts). We show that the polar cap is a particularly intricate region for the double-probe technique, where large nongeophysical fields regularly contaminate EFW measurments of the DC electric field. We present a model explaining this in terms of enhanced cold plasma wake effects appearing when the ion flow energy is higher than the thermal energy but below the spacecraft potential multiplied by the ion charge. We suggest that these conditions, which are typical of the polar wind and occur sporadically in other regions containing a significant low energy ion population, cause a large cold plasma wake behind the spacecraft, resulting in spurious electric fields in EFW data. This interpretation is supported by an analysis of the direction of the spurious electric field, and by showing that use of active potential control alleviates the situation.

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Section: Implications For Other Regionsmentioning

confidence: 99%

Electric field measurements on Cluster: comparing the double-probe and electron drift techniques

et al. 2006

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“…This socalled tongue of ionization (TOI) connects the plume with cusp ion outflow (e.g., Zeng and Horowitz, 2008;Walsh et al, 2014b) and dense ionospheric density contributions to the plasma sheet (e.g., Elphic et al, 1997;Borovsky et al, 1997). There has been considerable modeling of the ionospheric SED plume (e.g., Lin et al, 2005) and of the plasmaspheric plume (e.g., Huba and Krall, 2013), but recently the first self-consistent model of the ionosphere and magnetosphere electric field drivers has been done with the SAMI3-RCM simulation of the 31 March 2001 geomagnetic storm (Huba and Sazykin, 2014).…”

Section: Sed Plumementioning

confidence: 99%

The story of plumes: the development of a new conceptual framework for understanding magnetosphere and ionosphere coupling

2016

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Abstract. The name "plume" has been given to a variety of plasma structures in the Earth's magnetosphere and ionosphere. Some plumes (such as the plasmasphere plume) represent elevated plasma density, while other plumes (such as the equatorial F region plume) represent low-density regions. Despite these differences these structures are either directly related or connected in the causal chain of plasma redistribution throughout the system. This short review defines how plumes appear in different measurements in different regions and describes how plumes can be used to understand magnetosphere-ionosphere coupling. The story of the plume family helps describe the emerging conceptual framework of the flow of high-density-low-latitude ionospheric plasma into the magnetosphere and clearly shows that strong two-way coupling between ionospheric and magnetospheric dynamics occurs not only in the high-latitude auroral zone and polar cap but also through the plasmasphere. The paper briefly reviews, highlights and synthesizes previous studies that have contributed to this new understanding.

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“…If we input these controlling parameters to the model, electric field at any ionospheric location at high latitudes can be calculated so that this model is employed in many works (e.g. Elphic et al, 1997;Jordanova et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Derivation of inner magnetospheric electric field (UNH-IMEF) model using Cluster data set

et al. 2008

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Abstract.We derive an inner magnetospheric electric field (UNH-IMEF) model at L=2-10 using primarily Cluster electric field data for more than 5 years between February 2001 and October 2006. This electric field data set is divided into several ranges of the interplanetary electric field (IEF) values measured by ACE. As ring current simulations which require electric field as an input parameter are often performed at L=2-6.6, we have included statistical results from ground radars and low altitude satellites inside the perigee of Cluster in our data set (L∼4). Electric potential patterns are derived from the average electric fields by solving an inverse problem. The electric potential pattern for small IEF values is probably affected by the ionospheric dynamo. The magnitudes of the electric field increase around the evening local time as IEF increases, presumably due to the sub-auroral polarization stream (SAPS). Another region with enhanced electric fields during large IEF periods is located around 9 MLT at L>8, which is possibly related to solar windmagnetosphere coupling. Our potential patterns are consistent with those derived from self-consistent simulations. As the potential patterns can be interpolated/extrapolated to any discrete IEF value within measured ranges, we thus derive an empirical electric potential model. The performance of the model is evaluated by comparing the electric field derived from the model with original one measured by Cluster and mapped to the equator. The model is open to the public through our website.

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The fate of the outer plasmasphere

Cited by 74 publications

References 19 publications

Electric field measurements on Cluster: comparing the double-probe and electron drift techniques

Electric field measurements on Cluster: comparing the double-probe and electron drift techniques

The story of plumes: the development of a new conceptual framework for understanding magnetosphere and ionosphere coupling

Derivation of inner magnetospheric electric field (UNH-IMEF) model using Cluster data set

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