Electromagnetic Ion Cyclotron (EMIC) wave are important for the losses of ultra-relativistic electrons from the Earth''s radiation belts. In this work, statistical EMIC diffusion coefficients are calculated from Van Allen Probe A observations of EMIC waves from the entire mission. The diffusion coefficient calculations include the observed L* and activity dependent distributions in plasma density and wave spectra so that the wave-particle interactions modelled are representative of those in the radiation belts. These diffusion coefficients can be included into global radiation belt simulations such as the BAS radiation belt model. The study is published in Ross et al 2021, JGR: Space Physics. Funding was provided by National Environment Research Council Highlight Topic grant NE/P01738X/1 (Rad-Sat), National Environment Research Council grant NE/R016445/1 and NE/R016038/1.

The banded structure of Electromagnetic Ion Cyclotron (EMIC) wave spectra and their resonant interactions with radiation belt electrons depend on the cold ion composition. However, there is a great deal of uncertainty in the composition in the inner magnetosphere due to difficulties in direct flux measurements. Here we determine the sensitivity of electron diffusion by EMIC waves to the cold ion composition. The diffusion coefficients are calculated using collocated EMIC waves spectra and plasma densities observed by Van Allen Probe Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) data, parameterised by Dst, using quasi-linear theory implemented in the Pitch-Angle Diffusion of Ions and Electrons (PADIE) code. Funding was provided by NERC Highlight Topic grant: NE/P01738X/1 (Rad-Sat), NERC grant: NE/V00249X/1 (Sat-Risk) and NERC grant: NE/R016038/1