Symmetric Ring Current Research Articles

Observations of Earth's bow shock for low mach numbers

Four anomalous Earth's bow shock locations observed during 1969 are studied, using plasma and magnetic field data from the European satellite HEOS-1. The results show that when no magnetic storms are present, the shock position is predicted with a good approximation by magnetohydrodynamic equations, making use of the magnetosonic Mach number of the solar wind. When magnetic storms are present, symmetric and asymmetric ring currents should be taken into account. For low magnetosonic Mach numbers (1 < M MS ≲ 3), the magnetosheath magnetic field is characterized by the unusual absence of low frequency turbulence. This experimental result seems to indicate that under such conditions the bow shock is a laminar shock.

Unified theory of SAR arc formation at the plasmapause

Stable auroral red arcs generation at plasmapause from ion cyclotron wave turbulent dissipation of ring current proton energy

A revised (B, L) coordinate system to allow for distention of the magnetosphere by a symmetric ring current

The McIlwain (B, L) coordinate system for describing physical points within the magnetosphere is modified to take account of magnetospheric distortions arising from symmetric ring currents, their associated induction fields, and a constant magnetopause boundary field on the day side of the earth. The goal in making such a modification is to develop a general procedure whereby stormtime magnetospheric distortions may be separated out of satellite particle data, making it possible to observe some of the more subtle aspects of particle behavior that otherwise may be hidden by larger effects. To demonstrate the usefulness of the modified (B, L) system, some new cases of Explorer 12 particle detector data are presented in which the particle configuration appears to be undergoing radial diffusion when plotted in the standard (B, L) system. However, when the counting rates are replotted in the modified system that accounts for ring currents, the diffusion is no longer evident. These cases are thus at least partially explained as being the effect of gross motion of the field lines themselves, rather than particle motion through the field lines.

Asymmetric ring currents and the low-latitude disturbance daily variation

An asymmetric ring current belt consisting of a symmetric ring current and a superimposed partial ring current system is proposed as the explanation for the low-latitude disturbance daily variation. The magnetic effects of the partial ring current system are derived using a scale model together with a small magnetometer as an analog computer. The magnetic field of an asymmetric ring current belt is derived by assigning an amplitude A to the partial ring current function and an amplitude S to the (constant) symmetric ring current function. The span in longitude, the initial position in local time, and the local-time drift rate of the partial ring current are also adjustable parameters in the asymmetric ring current model. Recovery phases for stations with various longitudes are derived by assuming exponential decays for the partial ring current and symmetric ring current. Measured and computed recovery phases are compared for a few magnetic storms. The comparisons show that even this very simple model of the asymmetric ring current can account for most of the low-latitude disturbance daily variation in the recovery phase.