Regional particle simulations and global two-fluid modelling of the magnetospheric current system

1995 ◽  
pp. 71-80 ◽  
Author(s):  
R. M. Winglee
Keyword(s):  
Current System ◽  
Particle Simulations ◽  
Two Fluid ◽  
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 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

scholarly journals Mercury’s Ring Current: MESSENGER Observations and Test-Particle Simulations

2021 ◽  
Author(s):  
Jiutong Zhao ◽  
Qiugang Zong ◽  
Chao Yue ◽  
Weijie Sun ◽  
Hui Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Test Particle ◽  
Ring Current ◽  
Current System ◽  
Wind Forcing ◽  
Particle Simulation ◽  
Space Environment ◽  
Magnetic Field Model ◽  
Particle Simulations

Abstract Energetic protons can carry a longitudinal electric current via their gradient and curvature drift around a planet and form a current system known as the ring current. The ring current has been observed in the intrinsic magnetosphere of Earth, Jupiter, and Saturn. However, there is still lacking evidence of ring current in Mercury’s magnetosphere, which contains significantly weaker and oppressive “dipolar” magnetic field and the charged particles are thought able to efficiently escape the magnetosphere through magnetopause shadowing and/or directly hitting the surface. Here we present the first observational evidence of Mercury ring current with the measurement of MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER). The ring current is bifurcated under moderate solar wind forcing, which is caused by the off-equatorial magnetic minima on the noon side and tends to vanish during weak solar wind forcing. This morphology is validated by a test-particle simulation with a Mercury’s dynamic magnetic field model. The total energy stored in the ring current exceeds 5x1010 J during active times, indicating that magnetic storms may also occur in Mercury’s magnetosphere.

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