@article{c28859f47a254947bfe63297d54cf7e9,
title = "Spatial dependence of electromagnetic ion cyclotron waves triggered by solar wind dynamic pressure enhancements",
abstract = "In this paper, using the multisatellite (the Van Allen Probes and two GOES satellites) observations in the inner magnetosphere, we examine two electromagnetic ion cyclotron (EMIC) wave events that are triggered by Pdyn enhancements under prolonged northward interplanetary magnetic field quiet time preconditions. For both events, the impact of enhanced Pdyn causes EMIC waves at multiple points. However, we find a strong spatial dependence that EMIC waves due to enhanced Pdyn impact can occur at multiple points (likely globally but not necessarily everywhere) but with different wave properties. For Event 1, three satellites situated at a nearly same dawnside zone but at slightly different L shells see occurrence of EMIC waves but in different frequencies relative to local ion gyrofrequencies and with different polarizations. These waves are found inside or at the outer edge of the plasmasphere. Another satellite near noon observes no dramatic EMIC wave despite the strongest magnetic compression there. For Event 2, the four satellites are situated at widely separated magnetic local time zones when they see occurrence of EMIC waves. They are again found at different frequencies relative to local ion gyrofrequencies with different polarizations and all outside the plasmasphere. We propose two possible explanations that (i) if triggered by enhanced Pdyn impact, details of ion cyclotron instability growth can be sensitive to local plasma conditions related to background proton distributions, and (ii) there can be preexisting waves with a specific spatial distribution, which determines occurrence and specific properties of EMIC waves depending on satellite's relative position after an enhanced Pdyn arrives.",
keywords = "EMIC waves, dynamic pressure",
author = "Cho, {J. H.} and Lee, {D. Y.} and Noh, {S. J.} and Hyomin Kim and Choi, {C. R.} and J. Lee and J. Hwang",
note = "Funding Information: This research at Chungbuk National University was supported partly by National Research Foundation of Korea (2016M1A3A3A02017017) and partly by the Korea Astronomy and Space Science Institute under the R&D program supervised by the Ministry of Science, ICT and Future Planning. The work at New Jersey Institute of Technology was supported by National Science Foundation (NSF) grant AGS-1547252 and the NASA Van Allen Probes RBSPICE instrument project by JHU/APL subcontract 937836270 to the New Jersey Institute of Technology under NASA Prime contract NAS5-01072. The Van Allen Probes data used for this paper can be obtained from NASA's CDAWeb FTP server, http://cdaweb.gsfc.nasa.gov, and at the EMFISIS website for the magnetic field and plasma density data, http://emfisis.physics.uiowa.edu/. The THEMIS data were provided by NASA's THEMIS mission team, and we acknowledge NASA contract NAS5-02099 and V. Angelopoulos for use of data from the THEMIS Mission. The THEMIS data used for this paper can be obtained from the THEMIS data website http://themis.ssl.berkeley.edu or from the THEMIS mission group at UCLA. The solar wind data used for this work were obtained at NASA's CDAWeb, OMNI FTP server, http://omniweb.gsfc.nasa.gov. The GOES magnetic field data can be obtained at ftp://satdat.ngdc.noaa.gov/sem/goes/data/new_full. The information on the magnetometer onboard GOES is available at http://www.swpc.noaa.gov/products/goes-magnetometer. The THEMIS data analysis software (TDAS) to calculate the WNA and ellipticity is freely available at the THEMIS website, http://themis.ssl.berkeley.edu/software.shtml. The output of the plasmapause test particle (PTP) simulation can be found at http://enarc.space.swri.edu/PTP. Publisher Copyright: {\textcopyright}2017. American Geophysical Union. All Rights Reserved.",
year = "2017",
month = may,
day = "1",
doi = "10.1002/2016JA023827",
language = "English (US)",
volume = "122",
pages = "5502--5518",
journal = "Journal of Geophysical Research: Space Physics",
issn = "2169-9380",
number = "5",
}