Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Possible evidence of virtual resonance in the dayside magnetosphere
AU - Takahashi, Kazue
AU - Berube, David
AU - Lee, Dong-Hun
AU - Goldstein, Jerry
AU - Singer, Howard J.
AU - Honary, Farideh
AU - Moldwin, Mark B.
N1 - Copyright (2009) American Geophysical Union. Further reproduction or electronic distribution is not permitted
PY - 2009/5/8
Y1 - 2009/5/8
N2 - On day 108, 2001, the Sub-Auroral Magnetometer Network (SAMNET) and Magnetometers along the Eastern Atlantic Seaboard for Undergraduate Research and Education (MEASURE) magnetometer arrays detected dayside magnetic pulsations at a common frequency of ∼15 mHz at all locations below L = 4. This global pulsation event was associated with alignment of the interplanetary magnetic field with the Sun-Earth axis, a condition known to generate ultralow-frequency (ULF) waves in front of the bow shock. The event occurred during the early recovery phase of a geomagnetic storm. Magnetic field measured by the GOES 8 geostationary satellite on the dayside indicated elevated broadband (7–80 mHz) ULF power in the compressional component without a strong peak at 15 mHz. These observations suggest that the global pulsations originated from a compressional magnetohydrodynamic eigenmode oscillation of the inner magnetosphere stimulated by a broadband external disturbance. The equatorial Alfvén velocity corresponding to the toroidal frequencies that were determined with the cross-phase analysis of SAMNET and MEASURE data showed a gradual decrease of the velocity with L without a clear signature of a plasmapause. The observed properties of the global pulsations are consistent with virtual resonance in the inner magnetosphere.
AB - On day 108, 2001, the Sub-Auroral Magnetometer Network (SAMNET) and Magnetometers along the Eastern Atlantic Seaboard for Undergraduate Research and Education (MEASURE) magnetometer arrays detected dayside magnetic pulsations at a common frequency of ∼15 mHz at all locations below L = 4. This global pulsation event was associated with alignment of the interplanetary magnetic field with the Sun-Earth axis, a condition known to generate ultralow-frequency (ULF) waves in front of the bow shock. The event occurred during the early recovery phase of a geomagnetic storm. Magnetic field measured by the GOES 8 geostationary satellite on the dayside indicated elevated broadband (7–80 mHz) ULF power in the compressional component without a strong peak at 15 mHz. These observations suggest that the global pulsations originated from a compressional magnetohydrodynamic eigenmode oscillation of the inner magnetosphere stimulated by a broadband external disturbance. The equatorial Alfvén velocity corresponding to the toroidal frequencies that were determined with the cross-phase analysis of SAMNET and MEASURE data showed a gradual decrease of the velocity with L without a clear signature of a plasmapause. The observed properties of the global pulsations are consistent with virtual resonance in the inner magnetosphere.
KW - magnetometer DCS-publications-id
KW - art-965
KW - DCS-publications-credits
KW - iono
KW - samnet
KW - DCS-publications-personnel-id
KW - 5
U2 - 10.1029/2008JA013898
DO - 10.1029/2008JA013898
M3 - Journal article
VL - 114
SP - 1
EP - 11
JO - Journal of Geophysical Research
JF - Journal of Geophysical Research
SN - 0148-0227
IS - A05206
ER -