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Magnetostatic Boundary Conditions

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An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...

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Implementation of a Hyperbolic Vortex Plasma Reactor for the Removal of Micropollutants in Water

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Near-Earth plasma sheet boundary dynamics during substorm dipolarization.

Rumi Nakamura¹, Tsugunobu Nagai², Joachim Birn³

¹1Space Research Institute, Austrian Academy of Sciences, Graz, Austria.

Earth, Planets, and Space : EPS

|February 4, 2020

Summary

Intense substorms cause large-scale dipolarization in Earth's magnetosphere. Multispacecraft data reveal vortex motion and field-aligned currents during this dynamic plasma sheet evolution.

Keywords:

Dipolarization Field-aligned current Plasma sheet boundary layer Substorm

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Area of Science:

Space Physics
Magnetospheric Physics
Plasma Physics

Background:

Substorms are dynamic events in Earth's magnetosphere, characterized by energy release and particle acceleration.
Dipolarization, a rapid change in magnetic field geometry, is a key feature of substorms in the near-Earth plasma sheet.
Understanding the large-scale evolution of dipolarization is crucial for comprehending magnetospheric dynamics and space weather.

Purpose of the Study:

To investigate the large-scale evolution of dipolarization during an intense substorm on August 10, 2016.
To analyze multispacecraft observations of plasma flow and magnetic field disturbances in the near-Earth magnetosphere.
To determine the role of vortex motion and field-aligned currents in substorm dynamics.

Main Methods:

Analysis of high-time-resolution magnetic field and plasma flow data from multiple spacecraft (Magnetospheric Multiscale, GOES, Geotail, Cluster).
Comparison of in-situ observations with ground-based magnetometer data (auroral electrojet indices).
Utilizing Magnetohydrodynamic (MHD) simulations to interpret observed phenomena.

Main Results:

Observed global dipolarization consisting of multiple short-timescale disturbances across a wide range of magnetic local time.
Detected distinct patterns of flow and field disturbances near plasma boundaries, suggesting vortex motion around localized flows.
Identified a new field-aligned current system associated with vortex motion, located off the equatorial side of R1/R2 systems.

Conclusions:

The study demonstrates that vortex motion around localized flows contributes to the formation of field-aligned currents during substorms.
Earthward flow braking and tailward evolving magnetic flux play significant roles in controlling near-Earth plasma sheet boundary dynamics.
Multispacecraft observations provide crucial insights into the complex, large-scale processes governing magnetospheric substorms.