### Abstract

A new reconstruction method is developed for two-dimensional (2-D), steady, magnetohydrostatic structures with anisotropic plasma pressure, which is assumed to be solely dependent on magnetic field strength. This dependence leads to a Poisson-like partial differential equation that can be solved as a spatial initial-value problem by use of data taken from a single spacecraft passing through a coherent structure. However, the resulting partial differential equation cannot be reduced to the ordinary Grad-Shafranov equation with isotropic pressure. The numerical code for new reconstruction is developed and successfully validated against an exact analytical solution. This new reconstruction method is first applied to examine 2-D geometry of magnetic mirror structures observed by the Magnetospheric Multiscale (MMS) spacecraft in the Earth's magnetosheath. The observed mirror structures satisfy the magnetohydrostatic conditions and are comoving with the average ion bulk flow. Using MMS1 measurements, the reconstruction produces a 2-D magnetic field map and distribution maps of pressures perpendicular and parallel to the magnetic field. The reconstructed field map reveals magnetic bottle-like structures as predicted by the mirror-mode theory. A very good agreement is achieved between observation and reconstruction for the other three MMS spacecraft not used for reconstruction. It is concluded that this new reconstruction is suitable for examining 2-D geometry of mirror structures.

Original language | English |
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Journal | Journal of Geophysical Research: Space Physics |

DOIs | |

Publication status | Published - 1 Jan 2019 |

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### Keywords

- Grad-Shafranov reconstruction
- magnetic mirror structure
- pressure anisotropy

### ASJC Scopus subject areas

- Geophysics
- Forestry
- Oceanography
- Aquatic Science
- Ecology
- Water Science and Technology
- Soil Science
- Geochemistry and Petrology
- Earth-Surface Processes
- Atmospheric Science
- Space and Planetary Science
- Earth and Planetary Sciences (miscellaneous)
- Palaeontology

### Cite this

**Two-Dimensional Reconstruction of Magnetic Mirror Structures With Pressure Anisotropy : Theory and Application.** / Wai Leong, Teh.

Research output: Contribution to journal › Article

}

TY - JOUR

T1 - Two-Dimensional Reconstruction of Magnetic Mirror Structures With Pressure Anisotropy

T2 - Theory and Application

AU - Wai Leong, Teh

PY - 2019/1/1

Y1 - 2019/1/1

N2 - A new reconstruction method is developed for two-dimensional (2-D), steady, magnetohydrostatic structures with anisotropic plasma pressure, which is assumed to be solely dependent on magnetic field strength. This dependence leads to a Poisson-like partial differential equation that can be solved as a spatial initial-value problem by use of data taken from a single spacecraft passing through a coherent structure. However, the resulting partial differential equation cannot be reduced to the ordinary Grad-Shafranov equation with isotropic pressure. The numerical code for new reconstruction is developed and successfully validated against an exact analytical solution. This new reconstruction method is first applied to examine 2-D geometry of magnetic mirror structures observed by the Magnetospheric Multiscale (MMS) spacecraft in the Earth's magnetosheath. The observed mirror structures satisfy the magnetohydrostatic conditions and are comoving with the average ion bulk flow. Using MMS1 measurements, the reconstruction produces a 2-D magnetic field map and distribution maps of pressures perpendicular and parallel to the magnetic field. The reconstructed field map reveals magnetic bottle-like structures as predicted by the mirror-mode theory. A very good agreement is achieved between observation and reconstruction for the other three MMS spacecraft not used for reconstruction. It is concluded that this new reconstruction is suitable for examining 2-D geometry of mirror structures.

AB - A new reconstruction method is developed for two-dimensional (2-D), steady, magnetohydrostatic structures with anisotropic plasma pressure, which is assumed to be solely dependent on magnetic field strength. This dependence leads to a Poisson-like partial differential equation that can be solved as a spatial initial-value problem by use of data taken from a single spacecraft passing through a coherent structure. However, the resulting partial differential equation cannot be reduced to the ordinary Grad-Shafranov equation with isotropic pressure. The numerical code for new reconstruction is developed and successfully validated against an exact analytical solution. This new reconstruction method is first applied to examine 2-D geometry of magnetic mirror structures observed by the Magnetospheric Multiscale (MMS) spacecraft in the Earth's magnetosheath. The observed mirror structures satisfy the magnetohydrostatic conditions and are comoving with the average ion bulk flow. Using MMS1 measurements, the reconstruction produces a 2-D magnetic field map and distribution maps of pressures perpendicular and parallel to the magnetic field. The reconstructed field map reveals magnetic bottle-like structures as predicted by the mirror-mode theory. A very good agreement is achieved between observation and reconstruction for the other three MMS spacecraft not used for reconstruction. It is concluded that this new reconstruction is suitable for examining 2-D geometry of mirror structures.

KW - Grad-Shafranov reconstruction

KW - magnetic mirror structure

KW - pressure anisotropy

UR - http://www.scopus.com/inward/record.url?scp=85063000051&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85063000051&partnerID=8YFLogxK

U2 - 10.1029/2018JA026416

DO - 10.1029/2018JA026416

M3 - Article

AN - SCOPUS:85063000051

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 2169-9380

ER -