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Some new thoughts on magnetospheric substorms
Author(s) -
Akasofu S.I.,
Kan J. R.
Publication year - 1973
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs008i011p01049
Subject(s) - substorm , magnetosphere , physics , solar wind , interplanetary magnetic field , earth's magnetic field , interplanetary spaceflight , geophysics , field line , interplanetary medium , dynamo , ionosphere , electrojet , astrophysics , magnetic field , quantum mechanics
Several important new observations of magnetospheric substorms now allow us to examine many substorm features in terms of the solar wind‐magnetosphere dynamo and of four rates, the merging rate M of the interplanetary and geomagnetic field lines, the transport rate T of the merged field lines from the dayside magnetosphere to the magnetotail, the reconnection rate R of the transported field lines and the return rate R of the reconnected field lines to the dayside magnetophere. It is shown that magnetospheric observations of great variety are consistently explainable by the deduced result that the expansive phase of a typical intense substorm occurs when the combination of the four rates is such thatwhile a weak substorm occurs when the combination of the four rates is such thatwhere an upward‐pointing arrow denotes an increasing rate. The first combination corresponds to a negative B z component of the interplanetary magnetic field, while the second one to a positive B z component. Thus, the B z component does not control triggering mechanisms of substorms, but does control the intensity of substorms. Indeed, there are also periods in which the combination may be such that M (∼ T )↑, ℜ = const., R = const., which does not consistently result in substorm activity.