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Magnetospheric equilibrium with anisotropic pressure

Technical Report ·
DOI:https://doi.org/10.2172/5730952· OSTI ID:5730952

Self-consistent magnetospheric equilibrium with anisotropic pressure is obtained by employing an iterative metric method for solving the inverse equilibrium equation in an optimal flux coordinate system. A method of determining plasma parallel and perpendicular pressures from either analytic particle distribution or particle distribution measured along the satellite's path is presented. The numerical results of axisymmetric magnetospheric equilibrium including the effects of finite beta, pressure anisotropy, and boundary conditions are presented for a bi-Maxwellian particle distribution. For the isotropic pressure cases, the finite beta effect produces an outward expansion of the constant magnetic flux surfaces in relation to the dipole field lines, and along the magnetic field the toroidal ring current is maximum at the magnetic equator. The effect of pressure anisotropy is found to further expand the flux surfaces outward. Along the magnetic field lines the westward ring current can be peak away from the equator due to an eastward current contribution resulting from pressure anisotropy. As pressure anisotropy increases, the peak westward current can become more singular. The outer boundary flux surface has significant effect on the magnetospheric equilibrium. For the outer flux boundary resembling dayside compressed flux surface due to solar wind pressure, the deformation of the magnetic field can be quite different from that for the outer flux boundary resembling the tail-like surface. 23 refs., 17 figs.

Research Organization:
Princeton Univ., NJ (USA). Plasma Physics Lab.
Sponsoring Organization:
DOE; NSF; USDOE, Washington, DC (USA); National Science Foundation, Washington, DC (USA)
DOE Contract Number:
AC02-76CH03073
OSTI ID:
5730952
Report Number(s):
PPPL-2762; ON: DE91015379; CNN: ATM-8911638
Country of Publication:
United States
Language:
English