Magnetospheric “magic” frequencies as magnetopause surface eigenmodes
File(s)supp2.pdf (616.09 KB) grl50979.pdf (920.42 KB)
Supporting information
Published version
Author(s)
Archer, MO
Hartinger, MD
Horbury, TS
Type
Journal Article
Abstract
Abstract. The persistent so-called “magic” magnetospheric frequencies are thought to be either directly driven by monochromatic solar wind pressure fluctuations or resonantly excited global (cavity/waveguide) or magnetopause surface eigenmodes. We distinguish between these cases by statistically investigating, using simultaneous observations, the magnetospheric response to jets in the subsolar magnetosheath. The broadband jets do not exhibit discrete frequencies, but do drive waves at the discrete “magic” frequencies, with both direct and resonant driving. We show that the expected fundamental frequencies of magnetopause surface eigenmodes have two preferential values over a wide range of upstream conditions, corresponding to fast and slow solar wind, and that their harmonics are in good agreement with the “magic” frequencies. We also show that the waves are largely inconsistent with global modes outside the plasmasphere. Thus we conclude that these “magic” frequencies are most likely due to magnetopause surface eigenmodes.
Date Issued
2013
Citation
Geophysical Research Letters, 2013, 40, pp.5003-5008
Start Page
5003
End Page
5008
Journal / Book Title
Geophysical Research Letters
Volume
40
Copyright Statement
© 2013. American Geophysical Union. All Rights Reserved.
Notes
owner: moa102 timestamp: 2013.08.06