Determining the Temporal and Spatial Coherence of Plasmaspheric Hiss Waves in the Magnetosphere

Plasmaspheric hiss is one of the most important plasma waves in Earth's magnetosphere to contribute radiation belt dynamics by pitch-angle scattering energetic electrons via wave-particle interactions. There growing evidence that temporal and spatial variability interactions are factors construction diffusion-based models belts. Hiss amplitudes thought be coherent across large distances on long timescales inside plasmapause, which means can act throughout their drift trajectories for many hours. In this study, we investigate both coherence plasmaspheric between two Van Allen Probes from November 2012 July 2019. We find ∼3,264 events where determine correlation wave as a function distance time lag order study hiss. The statistical results show decrease with increasing L-shell, become incoherent at L > ∼4.5. Inside = ∼4.5, within extent up ∼1,500 km ∼10 min. does not depend strongly geomagnetic index (AL*) or magnetic local time. discuss ramifications our relevance understanding global characteristics role dynamics.