Internally and externally induced deformations of the magnetospheric equatorial current as inferred from spacecraft data

Tsyganenko, N. A.; Andreeva, V. A.; Gordeev, E.

doi:10.5194/angeo-33-1-2015

Cited by 30 publications

(74 citation statements)

References 20 publications

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“…More data and satellites have become available since the work of Tsyganenko and Fairfield (2004). In total, 10 years (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010) of Cluster 1-4 (Balogh et al, 2001(Balogh et al, ), 19 years (1995(Balogh et al, -2013 of Geotail (Kokubun et al, 1994(Kokubun et al, ), 4 years (2004(Kokubun et al, -2007 of TC-1 (Carr et al, 2005), and 7 years (2007)(2008)(2009) for P1/P2; 2007-2013 for P3-P5) of THEMIS (Auster et al, 2008) magnetometer data are used in our study, with an original resolution of 4, 64, 60, and 3 s, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…Later, Tsyganenko and Fairfield (2004) found that an increase in solar wind dynamic pressure results in a decrease in the hinging distance H 0 . Recently, based on the model of Tsyganenko and Fairfield (2004), Tsyganenko et al (2015) developed a new quantitative model of the shape of the magnetospheric equatorial current sheet as a function of the dipole tilt angle, solar wind dynamic pressure, and IMF, and the model covers all local time, including the dayside sector.…”

Section: Introductionmentioning

confidence: 99%

“…To obtain an observational model of the neutral sheet, three major studies have been done in the last several decades, i.e., Fairfield (1980), Hammond et al (1994), and Tsyganenko and Fairfield (2004). Fairfield (1980) proposed a displaced Figure 1.…”

Section: Introductionmentioning

confidence: 99%

“…Tsyganenko and Fairfield (2004) developed an analytical approximation for the shape of the nightside tail current sheet with a semi-empirical model as a function of the Earth's dipole tilt angle, solar wind ram pressure, and the interplanetary magnetic field (IMF). The model of Tsyganenko and Fairfield (2004) was developed for covering a downtail distance from 0 to 50 R E , containing the region of the dipolar magnetic field. The shape of the neutral sheet can be greatly affected by the solar wind parameters, the IMF, and the dipole tilt angle (Russell, 1972;Sibeck et al, 1985;Tsyganenko and Fairfield, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…The model of Tsyganenko and Fairfield (2004) was developed for covering a downtail distance from 0 to 50 R E , containing the region of the dipolar magnetic field. The shape of the neutral sheet can be greatly affected by the solar wind parameters, the IMF, and the dipole tilt angle (Russell, 1972;Sibeck et al, 1985;Tsyganenko and Fairfield, 2004). Russell (1972Russell ( , 1973 predicted that the IMF B Y can twist the magnetotail neutral sheet.…”

Section: Introductionmentioning

confidence: 99%

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A statistical study on the shape and position of the magnetotail neutral sheet

Xiao

Zhang

et al. 2016

Ann. Geophys.

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Abstract. We study the average shape and position of the magnetotail neutral sheet based on magnetic field data obtained by Cluster, Geotail, TC-1, and THEMIS from the years 1995 to 2013. All data in the aberrated GSM (geocentric solar magnetospheric) coordinate system are normalized to the same solar wind pressure 2 nPa and downtail distance X ∼ −20R E . Our results show characteristics of the neutral sheet, as follows. (1) The neutral sheet assumes a greater degree of curve in the YZ cross section when the dipole tilt increases, the Earth dipole tilt angle affects the neutral sheet configuration not only in the YZ cross section but also in the XY cross section, and the neutral sheet assumes a more significant degree of tilt in the XY cross section when the dipole tilt increases. (2) Counterclockwise twisting of the neutral sheet with 3.10 • is observed, looking along the downtail direction, for the positive interplanetary magnetic field (IMF) B Y with a value of 3 to 8 nT, and clockwise twisting of the neutral sheet with 3.37 • for the negative IMF B Y with a value of −8 to −3 nT, and a northward IMF can result in a greater twisting of the near-tail neutral sheet than southward. The above results can be a reference to the neutral sheet model. Our large database also shows that the displaced ellipse model is effective to study the average shape of the neutral sheet with proper parameters when the dipole tilt angle is larger (less) than 10 • (−10 • ).

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A statistical study on the shape and position of the magnetotail neutral sheet

Xiao

Zhang

et al. 2016

Ann. Geophys.

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A forecasting model of the magnetosphere driven by an optimal solar wind coupling function

Tsyganenko

Andreeva

2015

JGR Space Physics

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A new empirical magnetospheric magnetic field model is described, driven by interplanetary parameters including a coupling function by Newell et al. (2007), termed henceforth as “N index.” The model uses data from Polar, Geotail, Cluster, and Time History of Events and Macroscale Interactions during Substorms satellites, obtained in 1995–2013 at distances 3–60 RE. The model magnetopause is based on Lin et al. (2010) boundary driven by the solar wind pressure, IMF Bz, and the geodipole tilt. The model field includes contributions from the symmetric ring current (SRC), partial ring current (PRC) with associated Region 2 field‐aligned currents (R2 FAC), tail, Region 1 (R1) FAC, and a penetrated IMF. Increase in the N index results in progressively larger magnitudes of all the field sources, the most dramatic and virtually linear growth being found for the PRC and R1 FAC. The solar wind dynamic pressure Pdyn affects the model magnetotail current in proportion to the factor []Pdyn/〈Pdyn〉ζ, where the exponent ζ on the order of 0.4–0.6 steadily decreases with increasing N index. The PRC peaks near midnight at N ∼ 0 but turns duskward with growing N. At ionospheric altitudes, both R1 and R2 FAC expand equatorward with growing N and Pdyn, and the R2 zone rotates westward. Larger values of N result in a more efficient penetration of the IMF into the magnetosphere and larger magnetic flux connection across the magnetopause. Growing dipole tilt is accompanied by a persistent and significant decrease of the total current in all magnetospheric field sources.

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Reconstructing the magnetosphere from data using radial basis functions

Andreeva

Tsyganenko

2016

JGR Space Physics

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A new method is proposed to derive from data magnetospheric magnetic field configurations without any a priori assumptions on the geometry of electric currents. The approach utilizes large sets of archived satellite data and uses an advanced technique to represent the field as a sum of toroidal and poloidal parts, whose generating potentials Ψ1 and Ψ2 are expanded into series of radial basis functions (RBFs) with their nodes regularly distributed over the 3‐D modeling domain. The method was tested by reconstructing the inner and high‐latitude field within geocentric distances up to 12RE on the basis of magnetometer data of Geotail, Polar, Cluster, Time History of Events and Macroscale Interactions during Substorms, and Van Allen space probes, taken during 1995–2015. Four characteristic states of the magnetosphere before and during a disturbance have been modeled: a quiet prestorm period, storm deepening phase with progressively decreasing SYM‐H index, the storm maximum around the negative peak of SYM‐H, and the recovery phase. Fitting the RBF model to data faithfully resolved contributions to the total magnetic field from all principal sources, including the westward and eastward ring current, the tail current, diamagnetic currents associated with the polar cusps, and the large‐scale effect of the field‐aligned currents. For two main phase conditions, the model field exhibited a strong dawn‐dusk asymmetry of the low‐latitude magnetic depression, extending to low altitudes and partly spreading sunward from the terminator plane in the dusk sector. The RBF model was found to resolve even finer details, such as the bifurcation of the innermost tail current. The method can be further developed into a powerful tool for data‐based studies of the magnetospheric currents.

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Internally and externally induced deformations of the magnetospheric equatorial current as inferred from spacecraft data

Cited by 30 publications

References 20 publications

A statistical study on the shape and position of the magnetotail neutral sheet

A statistical study on the shape and position of the magnetotail neutral sheet

A forecasting model of the magnetosphere driven by an optimal solar wind coupling function

Reconstructing the magnetosphere from data using radial basis functions

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