Geomagnetic and solar wind fluctuations at discrete frequencies: A case study

摘要

abstract_textpA worldwide analysis of geomagnetic field measurements, during a period of wave activity following an intense magnetospheric perturbation, revealed signals at discrete frequencies (f approximate to 1.0, approximate to 1.9, approximate to 2.2-2.4, approximate to 2.6, approximate to 3.4-3.6, and approximate to 4.7 mHz) which are similar to the frequencies identified from auroral to low latitudes in previous investigations. All the power enhancements found correspondence in enhancements, approximately at the same frequencies, in the solar wind dynamic pressure, and/or speed and interplanetary magnetic field components. The modes dominant in the wide afternoon sector (f approximate to 1.9, approximate to 2.6, and approximate to 3.4-3.6 mHz) were almost ubiquitously detected, and rough estimates of the propagation parameters appear consistent with those expected for standing cavity modes. The modes emerging in the morning sector (f approximate to 1.0 and approximate to 2.2-2.4 mHz) appear related to the fluctuations of the magnetopause current, driven by those of the solar wind pressure. Citation: Villante, U., A. Del Corpo, and P. Francia (2013), Geomagnetic and solar wind fluctuations at discrete frequencies: A case study, J. Geophys. Res. Space Physics, 118, 218-231, doi:10.1029/2012JA017971./p/abstract_text