scholarly journals Bow shock and magnetopause contributions to the magnetospheric current system: Hints from the Cluster observations

2012 ◽  
Vol 117 (A1) ◽  
Author(s):  
B. B. Tang ◽  
C. Wang ◽  
X. C. Guo
Keyword(s):  
Current System ◽  
Bow Shock ◽  
Magnetospheric Current System

scholarly journals Study of the applicability of the curlometer technique with the four Cluster spacecraft in regions close to Earth

2012 ◽  
Vol 30 (3) ◽  
pp. 597-611 ◽  
Author(s):  
S. Grimald ◽  
I. Dandouras ◽  
P. Robert ◽  
E. Lucek
Keyword(s):  
Magnetic Field ◽  
Current Density ◽  
Ring Current ◽  
Current System ◽  
Sufficient Conditions ◽  
Magnetic Activity ◽  
Inner Magnetosphere ◽  
Good Proxy ◽  
The Magnetic Field ◽  
Magnetospheric Current System

Abstract. Knowledge of the inner magnetospheric current system (intensity, boundaries, evolution) is one of the key elements for the understanding of the whole magnetospheric current system. In particular, the calculation of the current density and the study of the changes in the ring current is an active field of research as it is a good proxy for the magnetic activity. The curlometer technique allows the current density to be calculated from the magnetic field measured at four different positions inside a given current sheet using the Maxwell-Ampere's law. In 2009, the CLUSTER perigee pass was located at about 2 RE allowing a study of the ring current deep inside the inner magnetosphere, where the pressure gradient is expected to invert direction. In this paper, we use the curlometer in such an orbit. As the method has never been used so deep inside the inner magnetosphere, this study is a test of the curlometer in a part of the magnetosphere where the magnetic field is very high (about 4000 nT) and changes over small distances (ΔB = 1nT in 1000 km). To do so, the curlometer has been applied to calculate the current density from measured and modelled magnetic fields and for different sizes of the tetrahedron. The results show that the current density cannot be calculated using the curlometer technique at low altitude perigee passes, but that the method may be accurate in a [3 RE; 5 RE] or a [6 RE; 8.3 RE] L-shell range. It also demonstrates that the parameters used to estimate the accuracy of the method are necessary, but not sufficient conditions.

scholarly journals Statistical survey of day-side magnetospheric current flow using Cluster observations: Bow shock

2018 ◽  
Author(s):  
Evelyn Liebert ◽  
Christian Nabert ◽  
Karl-Heinz Glassmeier
Keyword(s):  
Current Flow ◽  
Current System ◽  
Bow Shock ◽  
Fluxgate Magnetometer ◽  
Good Accordance ◽  
Magnetometer Data ◽  
Current Densities ◽  
Simulation Results ◽  
Statistical Survey

Abstract. We present the first comprehensive statistical survey of the day-side terrestrial bow shock current system based on a large number of Cluster spacecraft bow shock crossings. Calculating the 3-D current densities using Fluxgate Magnetometer data and the Curlometer technique enables the investigation of current locations, directions and magnitudes in dependence on arbitrary IMF orientation. In case of quasi-perpendicular shock geometries we find that the current properties are in good accordance to theory and existing simulation results. However, currents at quasi-parallel shock geometries next to the foreshock region underlie distinct variations regarding their directions.

scholarly journals Statistical survey of day-side magnetospheric current flow using Cluster observations: bow shock

2018 ◽  
Vol 36 (4) ◽  
pp. 1073-1080 ◽  
Author(s):  
Evelyn Liebert ◽  
Christian Nabert ◽  
Karl-Heinz Glassmeier
Keyword(s):  
Current Flow ◽  
Current System ◽  
Bow Shock ◽  
Fluxgate Magnetometer ◽  
Good Accordance ◽  
Magnetometer Data ◽  
Current Densities ◽  
Simulation Results ◽  
Statistical Survey

Abstract. We present the first comprehensive statistical survey of the day-side terrestrial bow shock current system based on a large number of Cluster spacecraft bow shock crossings. Calculating the 3-D current densities using fluxgate magnetometer data and the curlometer technique enables the investigation of current locations, directions, and magnitudes in dependence on arbitrary IMF orientation. In case of quasi-perpendicular shock geometries we find that the current properties are in good accordance with theory and existing simulation results. However, currents at quasi-parallel shock geometries next to the foreshock region underlie distinct variations regarding their directions.

scholarly journals Computational analysis of the near-Earth magnetospheric current system during two-phase decay storms

2001 ◽  
Vol 106 (A12) ◽  
pp. 29531-29542 ◽  
Author(s):  
M. W. Liemohn ◽  
J. U. Kozyra ◽  
C. R. Clauer ◽  
A. J. Ridley
Keyword(s):  
Computational Analysis ◽  
Current System ◽  
Two Phase ◽  
Magnetospheric Current System
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