TY - JOUR

T1 - A GLOBAL ANALYTICAL REPRESENTATION OF THE MAGNETIC-FIELD PRODUCED BY THE REGION-2 BIRKELAND CURRENTS AND THE PARTIAL RING CURRENT

AU - TSYGANENKO, NA

PY - 1993/4/1

Y1 - 1993/4/1

N2 - A quantitative model is developed of the magnetic field produced by the electric current system of region 2 Birkeland currents, closed via the partial ring current. The distribution of j(perpendicular-to) is computed from a given axially asymmetric spatial distribution of hot isotropic magnetospheric plasma over an infinitely thin L shell in an axisymmetric purely dipolar geomagnetic field, while the field-aligned current density is found from the continuity of the net electric current. The magnetic field distribution is derived by a Biot-Savart integral over the electric current system. An assumed cosine dependence of the plasma pressure on local time makes it possible to reduce the problem of analytical representation of the B field to two dimensions, The obtained numerical fits for the partial ring current/region 2 Birkeland current magnetic field are relatively simple, continuous, and valid throughout the whole extraterrestrial space from ionospheric heights up to tens of R(E). To our knowledge, this is a first global analytical representation for the magnetic field of the partial ring current system which can be incorporated in future advanced models of the external geomagnetic field.

AB - A quantitative model is developed of the magnetic field produced by the electric current system of region 2 Birkeland currents, closed via the partial ring current. The distribution of j(perpendicular-to) is computed from a given axially asymmetric spatial distribution of hot isotropic magnetospheric plasma over an infinitely thin L shell in an axisymmetric purely dipolar geomagnetic field, while the field-aligned current density is found from the continuity of the net electric current. The magnetic field distribution is derived by a Biot-Savart integral over the electric current system. An assumed cosine dependence of the plasma pressure on local time makes it possible to reduce the problem of analytical representation of the B field to two dimensions, The obtained numerical fits for the partial ring current/region 2 Birkeland current magnetic field are relatively simple, continuous, and valid throughout the whole extraterrestrial space from ionospheric heights up to tens of R(E). To our knowledge, this is a first global analytical representation for the magnetic field of the partial ring current system which can be incorporated in future advanced models of the external geomagnetic field.

KW - magnetosphere

KW - ring current

KW - Birkeland currents

KW - Geomagnetic field

KW - modeling

U2 - 10.1029/92JA02002

DO - 10.1029/92JA02002

M3 - Article

VL - 98

SP - 5677

EP - 5690

JO - Journal of Geophysical Research: Biogeosciences

JF - Journal of Geophysical Research: Biogeosciences

SN - 0148-0227

IS - A4

ER -