Abstract
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, theta(k), of chorus becomes more oblique near the plume edge. Occurrence rates of theta(k) > 35 degrees on the plume boundary are approximately double that observed further away from the plume.
Whilst the increase in theta(k) is apparent on both plume edges, the distribution of theta(k) exhibits different behavior between the Eastward and Westward boundaries. In general, the distribution of azimuthal wave vector angles, phi(k), is symmetric about the anti-Earthwards direction.
However, near the Eastward plume boundary, an Eastwards skew of phi(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.