  Characteristics of electromagnetic ion cyclotron (EMIC) waves detected by the
Van Allen probes are statistically analyzed, particularly wave-band, bandwidth,
and time duration. The Electric and Magnetic Field Instrument Suite and
Integrated Science, an instrument on board the Van Allen Probes, provides the
necessary magnetic field measurements to examine 33 months of EMIC wave
occurrence (1 September 2013 to 31 May 2016). Upon visual identification, the
waves are grouped into their respective wave-bands, H+, He+, or O+, defined by
the frequencies they are observed at, manifested in the daily spectrograms as
their location relative to gyrofrequency lines. Nearly 2,500 EMIC wave events
are detected. Results suggest a prevalence of He+-band waves, and a rarity of
O+-band waves (1,155 H+-band events, 1,176 He+-band events, and 125 O+-band
events). The most prevalent bandwidth range for events in general is found to
be 0.25 - 0.5 Hz. However, this appears to vary among the three wave-bands.
Helium and oxygen wave-band events tend to have shorter bandwidths (0.25 - 0.5
Hz) than their hydrogen counterparts. Time duration is more consistent among
wave-bands, and while H+-band events on average have a slightly shorter
duration, the most common time duration for all wave-bands is between 20 and 40
minutes.
