The occurrence and wave properties of H <sup>+</sup> -, He <sup>+</sup> -, and O <sup>+</sup> -band EMIC waves observed by the Van Allen Probes

TitleThe occurrence and wave properties of H + -, He + -, and O + -band EMIC waves observed by the Van Allen Probes
Publication TypeJournal Article
Year of Publication2015
AuthorsSaikin, AA, Zhang, J-C, Allen, RC, Smith, CW, Kistler, LM, Spence, HE, Torbert, RB, Kletzing, CA, Jordanova, VK
JournalJournal of Geophysical Research: Space Physics
Date Published09/2015
KeywordsEMIC waves; Fast Fourier Transform; spatial distribution; Van Allen Probes
AbstractWe perform a statistical study of electromagnetic ion cyclotron (EMIC) waves detected by the Van Allen Probes mission to investigate the spatial distribution of their occurrence, wave power, ellipticity, and normal angle. The Van Allen Probes have been used which allow us to explore the inner magnetosphere (1.1 to 5.8 Re). Magnetic field measurements from the Electric and Magnetic Field Instrument Suite and Integrated Science onboard the Van Allen Probes are used to identify EMIC wave events for the first 22 months of the mission operation (8 September 2012 – 30 June 2014). EMIC waves are examined in H+-, He+-, and O+-bands. Over 700 EMIC wave events have been identified over the three different wave bands (265 H+-band events, 438 He+-band events, and 68 O+-band events). EMIC wave events are observed between L = 2 – 8, with over 140 EMIC wave events observed below L = 4. Results show that H+-band EMIC waves have two peak MLT occurrence regions: pre-noon (0900 < MLT ≤ 1200) and afternoon (1500 < MLT ≤ 1700) sectors. He+-band EMIC waves feature an overall stronger dayside occurrence. O+-band EMIC waves have one peak region located in the morning sector at lower L-shells (L < 4). He+-band EMIC waves average the highest wave power overall (>0.1 nT2/Hz), especially in the afternoon sector. Ellipticity observations reveal that linearly polarized EMIC wave dominate in lower L-shells.
Short TitleJ. Geophys. Res. Space Physics

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