@article{2602d33d03ca4c43a7cc86c0712c1350,
title = "Simultaneous space and ground-based observations of a plasmaspheric virtual resonance",
abstract = "We present simultaneous space and ground-based observations of Pi2 pulsations which occurred during a substorm on 25 September 2014. The timeline for this event starts at ∼06:04 UT when the THEMIS probe D located inside the plasmasphere detected Pi2 pulsations in the electric and magnetic fields. Cross-spectral analysis shows the azimuthal electric field and compressional magnetic field oscillated nearly in quadrature, highly suggestive of a standing fast-mode wave. Simultaneous Pi2 observations from dayside and nightside ground magnetometers at low latitudes indicate a global wave mode. A latitudinal magnetometer chain on the nightside observed a phase reversal in the H component of the Pi2 pulsations when crossing the footprint of the plasmapause, estimated from THEMIS spacecraft measurements. Spectral analysis of data from ground magnetometers in this latitudinal chain showed fundamental and second harmonic spectral peaks in their H and D components. Similar pulsation signatures at comparable harmonic frequencies were observed by three midlatitude SuperDARN HF radars, both poleward and equatorward of the plasmapause ionospheric footprint. Finally, the longitudinal polarization pattern and azimuthal phase propagation of midlatitude Pi2 pulsations are consistent with previous observations of a plasmaspheric virtual resonance being excited by a longitudinally localized source near midnight.",
keywords = "Pi2 pulsations, SuperDARN radars, multipoint observations, plasmaspheric virtual resonance",
author = "X. Shi and Baker, {J. B.H.} and Ruohoniemi, {J. M.} and Hartinger, {M. D.} and Nathaniel Frissell and Jiang Liu",
note = "Funding Information: The Virginia Tech authors acknowledge the support of the NSF under grants AGS-1341918 and AGS-1342968. N.A. Frissell is supported by NSF grant PLR-1443507. J. Liu is supported by NASA grant NNX14AC17G, NASA contract NAS5-02099, and NSF grant 1401822. The authors acknowledge the use of SuperDARN data, which are freely available through the SuperDARN website at Virginia Polytechnic Institute and State University (http://vt.superdarn.org/). SuperDARN is a collection of radars funded by National Scientific Funding Agencies of Australia, Canada, China, France, Japan, South Africa, United Kingdom, and United States of America. We acknowledge NASA contract NAS5-02099 and V. Angelopoulos for the use of data from the THEMIS Mission (http://themis.ssl.berkeley.edu/), specifically, J.W. Bonnell and F.S. Mozer for the use of EFI data; K.H. Glassmeier, U. Auster, and W. Baumjohann for the use of FGM data; S. Mende and C.T. Russell for the use of the GMAG data and NSF for support through grant AGS-1004814; and I.R. Mann, D.K. Milling, and the rest of the CARISMA team for the use of GMAG data (http://carisma.ca/). The authors also thank the ISEE, Nagoya University, INTERMAGNET, and the AMBER team for providing the ground magnetometer data. The results presented in this paper rely on data collected at magnetic observatories. We thank the national institutes that support them and INTERMAGNET for promoting high standards of magnetic observatory practice (http://www.intermagnet.org). Publisher Copyright: {\textcopyright}2017. American Geophysical Union. All Rights Reserved.",
year = "2017",
month = apr,
day = "1",
doi = "10.1002/2016JA023583",
language = "English (US)",
volume = "122",
pages = "4190--4209",
journal = "Journal of Geophysical Research: Space Physics",
issn = "2169-9380",
number = "4",
}