Open AccessThe use of a model current wedge in the determination of the position of substorm current systems
Author(s) -
M. Cramoysan,
R. J. Bunting,
D. Orr
Publication year - 1995
Publication title -
annales geophysicae
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.522
H-Index - 93
eISSN - 1432-0576
pISSN - 0992-7689
DOI - 10.1007/s00585-995-0583-0
Subject(s) - substorm , electrojet , wedge (geometry) , current (fluid) , geophysics , latitude , geology , breakup , geodesy , magnetometer , dipole , physics , earth's magnetic field , magnetosphere , magnetic field , mechanics , optics , oceanography , quantum mechanics
We present a technique for determination ofthe position and extent of the current systems present during substorm breakup.The parameters of a three-dimensional model of the currents are determined byfitting the model to data from the SAMNET magnetometer array, a midlatitudearray of seven stations. The model used is a fully 3D current wedge alignedalong dipolar field lines, the parameters being the meridians of upward anddownward field-aligned currents (FACs), the latitude of the auroral electrojetand the magnitude of current growth over the observation interval. The method isnovel in that the three geometrical parameters are first determined with thefourth arrived at via a secondary process. It has been applied to a number ofevents and appears to make estimates of the longitudes of the FACs consistentwith the predictions of previous methods. Since the method employs a fully 3Dmodel of the substorm current wedge as opposed to an idealised 2D model, it isreasonable to place more reliance on the results so obtained. Moreover, themethod also has the additional benefit of a prediction of the latitude of thesubstorm electrojet and the nature of the current growth through the wedge atsubstorm onset