Applying the cold plasma dispersion relation to whistler mode chorus waves: EMFISIS wave measurements from the Van Allen Probes

The Electric and Magnetic Fields Instrument Suite and Integrated Science (EMFISIS): Science, Data, and Usage Best Practices

We provide a post-mission assessment of the science and data from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) investigation on the NASA Van Allen Probes mission. An overview of important scientific results is presented, covering all of the key wave modes and DC magnetic fields measured by EMFISIS. Discussion of the data products, which are publicly available, follows to provide users with guidance on characteristics and known issues of the measurements. We present guidance on the correct use of derived products, in particular, the wave-normal analysis (WNA) which yields fundamental wave properties such as polarization, ellipticity, and Poynting flux. We also give information about the plasma density derived from measuring the upper hybrid line in the inner magnetosphere.

The Angular Distribution of Lower Band Chorus Waves Near Plasmaspheric Plumes

Plumes have been identified as an access region for chorus waves to enter the plasmasphere. Here, for the first time, chorus wave properties are parameterized by distance from the plume boundary. Case studies and statistical analysis indicate that the polar wave vector angle, θ _k , of chorus becomes more oblique near the plume edge. Occurrence rates of θ _k > 35° on the plume boundary are approximately double that observed further away from the plume. Whilst the increase in θ _k is apparent on both plume edges, the distribution of θ _k exhibits different behavior between the Eastward and Westward boundaries. In general, the distribution of azimuthal wave vector angles, ϕ _k , is symmetric about the anti-Earthwards direction. However, near the Eastward plume boundary, an Eastwards skew of ϕ _k is reported. This result provides new insight on chorus propagation in the context of the chorus-to-hiss mechanism, and has implications for quantifying wave-particle interactions in the near-plume region.