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

Lointier, G.; Darrouzet, F.; Décréau, Pierrette; Vallières, Xavier; Kougblénou, S.; Trotignon, J. G.; Rauch, Jean-Louis

doi:10.5194/angeo-31-217-2013

Cited by 13 publications

(18 citation statements)

References 81 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Each spacecraft carries 11 instruments. The WHISPER data allow determining the electron density inside and outside the plasmasphere (Décréau et al, 2001;Darrouzet et al, 2009b;Lointier et al, 2013). The frequency spectra obtained during the passive and active (sounding) operation modes of the instrument carry out a direct or indirect determination of the electron plasma frequency F P .…”

Section: Annmentioning

confidence: 99%

“…We have considered only the inbound crossings because the inbound and outbound ones were separated by only a few UT hours and a limited MLT difference (see, for instance, Figs. 1 and 3 of Lointier et al, 2013). We have further supplemented this sample by a second data set of plasmapause positions between July 2010 and December 2011 in order to have data from a time period with higher geomagnetic activity.…”

Section: Annmentioning

confidence: 99%

See 1 more Smart Citation

The relationship between plasmapause, solar wind and geomagnetic activity between 2007 and 2011

Verbanac

Pierrard

Bandić³

et al. 2015

Ann. Geophys.

Self Cite

View full text Add to dashboard Cite

Abstract. Taking advantage of the Cluster satellite mission and especially the observations made by the instrument WHISPER to deduce the electron number density along the orbit of the satellites, we studied the relationships between the plasmapause positions (L PP ) and the following L PP indicators: (a) solar wind coupling functions B z (Z component of the interplanetary magnetic field vector, B, in GSM system), BV (related to the interplanetary electric field; B is the magnitude of the interplanetary magnetic field vector, V is solar wind velocity), and d mp /dt (which combines different physical processes responsible for the magnetospheric activity) and (b) geomagnetic indices Dst, Ap and AE. The analysis is performed separately for three magnetic local time (MLT) sectors (Sector1 -night sector (01:00-07:00 MLT); Sector2 -day sector (07:00-16:00 MLT); Sector3 -evening sector (16:00-01:00 MLT)) and for all MLTs taken together. All L PP indicators suggest the faster plasmapause response in the postmidnight sector. Delays in the plasmapause responses (hereafter time lags) are approximately 2-27 h, always increasing from Sector1 to Sector3. The obtained fits clearly resolve the MLT structures. The variability in the plasmapause is the largest for low values of L PP indicators, especially in Sector2. At low activity levels, L PP exhibits the largest values on the dayside (in Sector2) and the smallest on the postmidnight side (Sector1). Displacements towards larger values on the evening side (Sector3) and towards lower values on the dayside (Sector2) are identified for enhanced magnetic activity. Our results contribute to constraining the physical mechanisms involved in the plasmapause formation and to further study the still not well understood related issues.

show abstract

Section: Annmentioning

confidence: 99%

Section: Annmentioning

confidence: 99%

The relationship between plasmapause, solar wind and geomagnetic activity between 2007 and 2011

Verbanac

Pierrard

Bandić³

et al. 2015

Ann. Geophys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…A more complex structure of the large scale plasmapause surface could also fit the observed ray path orientation. Actually, at large L values and under quiet magnetic conditions, the corotating magnetic field tubes are only partially replenished by ionospheric sources (Lointier et al, 2013). This could lead to complex 3-D shapes of the plasmasphere boundary, in particular during a surge of activity, when plasma irregularities can be possibly eroded from the plasmasphere .…”

Section: Morphologymentioning

confidence: 99%

Remote sensing of a NTC radio source from a Cluster tilted spacecraft pair

Décréau¹,

Kougblénou²,

Lointier³

et al. 2013

Ann. Geophys.

Self Cite

View full text Add to dashboard Cite

Abstract. The Cluster mission operated a "tilt campaign" during the month of May 2008. Two of the four identical Cluster spacecraft were placed at a close distance (∼ 50 km) from each other and the spin axis of one of the spacecraft pair was tilted by an angle of ∼ 46 • . This gave the opportunity, for the first time in space, to measure global characteristics of AC electric field, at the sensitivity available with long boom (88 m) antennas, simultaneously from the specific configuration of the tilted pair of satellites and from the available base of three satellites placed at a large characteristic separation (∼ 1 R E ). This paper describes how global characteristics of radio waves, in this case the configuration of the electric field polarization ellipse in 3-D-space, are identified from in situ measurements of spin modulation features by the tilted pair, validating a novel experimental concept. In the event selected for analysis, non-thermal continuum (NTC) waves in the 15-25 kHz frequency range are observed from the Cluster constellation placed above the polar cap. The observed intensity variations with spin angle are those of plane waves, with an electric field polarization close to circular, at an ellipticity ratio e = 0.87. We derive the source position in 3-D by two different methods. The first one uses ray path orientation (measured by the tilted pair) combined with spectral signature of magnetic field magnitude at source. The second one is obtained via triangulation from the three spacecraft baseline, using estimation of directivity angles under assumption of circular polarization. The two results are not compatible, placing sources widely apart. We present a general study of the level of systematic errors due to the assumption of circular polarization, linked to the second approach, and show how this approach can lead to poor triangulation and wrong source positioning. The estimation derived from the first method places the NTC source region in the dawn sector, at a large L value (L ∼ 10) and a medium geomagnetic latitude (35 • S). We discuss these untypical results within the frame of the geophysical conditions prevailing that day, i.e. a particularly quiet long time interval, followed by a short increase of magnetic activity.

show abstract

“…10). Lointier et al (2013) addressed the re-filling of the plasmasphere after an active period. They used Cluster active sounder data (giving absolute electron density between 0.2 and 80 cm −3 ) measured in 2002-2003 (perigee at 4 R E geocentric distance) and in 2007-2009 (perigee at 1.5 R E geocentric distance).…”

Section: Plasmasphere and Ring Currentmentioning

confidence: 99%

Recent highlights from Cluster, the first 3-D magnetospheric mission

et al. 2015

View full text Add to dashboard Cite

Abstract. The Cluster mission has been operated successfully for 14 years. During this time period, the evolution of the orbit has enabled Cluster to sample many more magnetospheric regions than was initially anticipated. So far, the separation of the Cluster spacecraft has been changed more than 30 times and has ranged from a few kilometres up to 36 000 km. These orbital changes have enabled the science team to address a wide variety of scientific objectives in key regions of Earth's geospace environment: the solar wind and bow shock, the magnetopause, polar cusps, magnetotail, plasmasphere and the auroral acceleration region. Recent results have shed new light on solar wind turbulence. They showed that the magnetosheath can be asymmetric under low Mach number and that it can contain density enhancement that may affect the magnetosphere. The magnetopause was found to be thinner and to have a higher current density on the duskside than on the dawnside. New methods have been used to obtain characteristic of the magnetotail current sheet and high-temporal-resolution measurements of electron pitch angle within flux transfer events (FTEs). Plasmaspheric wind has been discovered, and the refilling of the plasmasphere was observed for the first time over a very wide range of L shells. New models of global electric and magnetic fields of the magnetosphere have been obtained where Cluster, due to its polar orbit, has been essential. Finally, magnetic reconnection was viewed for the first time with high-resolution wave and electron measurements and acceleration of plasma was observed during times of varying rate of magnetic reconnection. The analysis of Cluster data was facilitated by the creation of the Cluster Science Data System (CSDS) and the Cluster Science Archive (CSA). Those systems were implemented to provide, for the first time for a plasma physics mission, a long-term public archive of all calibrated highresolution data from all instruments.

show abstract

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

Cited by 13 publications

References 81 publications

The relationship between plasmapause, solar wind and geomagnetic activity between 2007 and 2011

The relationship between plasmapause, solar wind and geomagnetic activity between 2007 and 2011

Remote sensing of a NTC radio source from a Cluster tilted spacecraft pair

Recent highlights from Cluster, the first 3-D magnetospheric mission

Contact Info

Product

Resources

About