Open AccessLong‐period hydromagnetic waves at very high geomagnetic latitudes
Author(s) -
Lanzerotti L. J.,
Shono A.,
Fukunishi H.,
Maclennan C. G.
Publication year - 1999
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/1999ja900325
Subject(s) - earth's magnetic field , magnetosphere , latitude , magnetopause , geophysics , geomagnetic secular variation , geomagnetic latitude , geology , physics , middle latitudes , atmospheric sciences , magnetic field , geodesy , geomagnetic storm , quantum mechanics
Low‐frequency (∼ 5 mHz) geomagnetic fluctuations are investigated at Antarctic ground‐based locations ranging from ∼ 71° to ∼ 80° geomagnetic latitude, and in the northern conjugate region. We show that a narrow band spectral feature at about this frequency often appears in the data, especially at the lower latitudes. We conclude that the demarcation in latitude between the appearance or not of the spectral tone indicates the location of the magnetopause, and that the ∼ 5 mHz frequency is the frequency of standing Alfvén waves on the last closed magnetosphere field lines.