scholarly journals The Scalable Plasma Ion Composition and Electron Density (SPICED) Model for Earth's Inner Magnetosphere

2021 ◽  
Vol 126 (9) ◽  
Author(s):  
Matthew K. James ◽  
Tim K. Yeoman ◽  
Petra Jones ◽  
Jasmine K. Sandhu ◽  
Jerry Goldstein
Keyword(s):  
Electron Density ◽  
Ion Composition ◽  
Inner Magnetosphere

scholarly journals Field line distribution of density at <I>L</I>=4.8 inferred from observations by CLUSTER

2009 ◽  
Vol 27 (2) ◽  
pp. 705-724 ◽  
Author(s):  
R. E. Denton ◽  
P. Décréau ◽  
M. J. Engebretson ◽  
F. Darrouzet ◽  
J. L. Posch ◽  
...  
Keyword(s):  
Field Line ◽  
Electron Density ◽  
Field Model ◽  
Mass Density ◽  
Local Maximum ◽  
Magnetic Equator ◽  
Alfven Wave ◽  
Ion Composition ◽  
Magnetic Field Model ◽  
Multiple Spacecraft

Abstract. For two events observed by the CLUSTER spacecraft, the field line distribution of mass density ρ was inferred from Alfvén wave harmonic frequencies and compared to the electron density ne from plasma wave data and the oxygen density nO+ from the ion composition experiment. In one case, the average ion mass M≈ρ/ne was about 5 amu (28 October 2002), while in the other it was about 3 amu (10 September 2002). Both events occurred when the CLUSTER 1 (C1) spacecraft was in the plasmatrough. Nevertheless, the electron density ne was significantly lower for the first event (ne=8 cm−3) than for the second event (ne=22 cm−3), and this seems to be the main difference leading to a different value of M. For the first event (28 October 2002), we were able to measure the Alfvén wave frequencies for eight harmonics with unprecedented precision, so that the error in the inferred mass density is probably dominated by factors other than the uncertainty in frequency (e.g., magnetic field model and theoretical wave equation). This field line distribution (at L=4.8) was very flat for magnetic latitude |MLAT|≲20° but very steeply increasing with respect to |MLAT| for |MLAT|≳40°. The total variation in ρ was about four orders of magnitude, with values at large |MLAT| roughly consistent with ionospheric values. For the second event (10 September 2002), there was a small local maximum in mass density near the magnetic equator. The inferred mass density decreases to a minimum 23% lower than the equatorial value at |MLAT|=15.5°, and then steeply increases as one moves along the field line toward the ionosphere. For this event we were also able to examine the spatial dependence of the electron density using measurements of ne from all four CLUSTER spacecraft. Our analysis indicates that the density varies with L at L~5 roughly like L−4, and that ne is also locally peaked at the magnetic equator, but with a smaller peak. The value of ne reaches a density minimum about 6% lower than the equatorial value at |MLAT|=12.5°, and then increases steeply at larger values of |MLAT|. This is to our knowledge the first evidence for a local peak in bulk electron density at the magnetic equator. Our results show that magnetoseismology can be a useful technique to determine the field line distribution of the mass density for CLUSTER at perigee and that the distribution of electron density can also be inferred from measurements by multiple spacecraft.

scholarly journals A neural network model of three-dimensional dynamic electron density in the inner magnetosphere

2017 ◽  
Vol 122 (9) ◽  
pp. 9183-9197 ◽  
Author(s):  
X. Chu ◽  
J. Bortnik ◽  
W. Li ◽  
Q. Ma ◽  
R. Denton ◽  
...  
Keyword(s):  
Neural Network ◽  
Electron Density ◽  
Network Model ◽  
Neural Network Model ◽  
Three Dimensional ◽  
Inner Magnetosphere

The Modulation of Plasma and Waves by Background Electron Density Irregularities in the Inner Magnetosphere

2020 ◽  
Vol 47 (15) ◽  
Author(s):  
Chao Yue ◽  
Qianli Ma ◽  
Chae‐Woo Jun ◽  
Jacob Bortnik ◽  
Qiugang Zong ◽  
...  
Keyword(s):  
Electron Density ◽  
Inner Magnetosphere ◽  
Electron Density Irregularities

scholarly journals Equatorial electron density measurements in Saturn's inner magnetosphere

2005 ◽  
Vol 32 (23) ◽  
Author(s):  
A. M. Persoon ◽  
D. A. Gurnett ◽  
W. S. Kurth ◽  
G. B. Hospodarsky ◽  
J. B. Groene ◽  
...  
Keyword(s):  
Electron Density ◽  
Inner Magnetosphere ◽  
Density Measurements

scholarly journals Self-consistent modelling of the daytime electron density profile in the ionospheric F region

1997 ◽  
Vol 15 (3) ◽  
pp. 314-326 ◽  
Author(s):  
A. Mikhailov ◽  
K. Schlegel
Keyword(s):  
Electron Density ◽  
Molecular Nitrogen ◽  
Molecular Ions ◽  
Ion Composition ◽  
Ion Temperature ◽  
Incoherent Scatter ◽  
Plasma Drift ◽  
F Region ◽  
Self Consistent ◽  
Exospheric Temperature

Abstract. A theoretical self-consistent method for the description of daytime Ne(h) profiles in the ionospheric F region measured by EISCAT is proposed. It is based on the use of a theoretical F-region model and measured electron density, Ne(h), electron, Te(h), and ion temperature, Ti(h), and field-aligned plasma drift Vl(h) profiles. The method describes the observed Ne(h) profile with high accuracy for quiet and disturbed conditions. Two versions of the method are considered: in the first the exospheric temperature Tex is derived from a procedure minimizing [log(Ne(h)obs / Ne(h)cal]2, in the second Tex is deduced from the ion energy conservation in the F region. The method allows us to infer from the incoherent-scatter observations: concentrations of atomic oxygen, [O], molecular oxygen, [O2], molecular nitrogen, [N2] the vertical plasma drift, W, the exospheric temperature. Tex, and the shape parameter S in the neutral temperature profile. The ratio ([O+]/Ne) calculated by the theoretical model is used to correct Te(h), Ti(h) and Ne(h) profiles routinely measured with EISCAT which are known to depend strongly on the actual applied ion-composition model. Such a correction is especially important for geomagnetically disturbed periods when the F region is strongly enriched with molecular ions. We conclude that four of the six thermospheric parameters, namely [O], [N2], W and Tex can be confidently inferred from the EISCAT observations, while the other two derived parameters, [O2] ans S are less reliable. The method can be used for the analysis of long-term (seasonal, solar cycle) as well as for day-to-day variations of the thermospheric parameters and the F-region ion composition using daytime incoherent-scatter observations.

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