Pitch angle scattering of energetic particles by oblique whistler waves

First order cyclotron or Landau resonant pitch angle scattering of electrons by oblique whistler waves propagating at large angles to the ambient field are found to be at least as large as that due to parallel propagating waves. Commonly observed precipitation of >40 keV electrons in association with ducted whistlers may thus be accompanied by substantial fluxes of lower energy (10 eV–40 keV) electrons precipitated by the nonducted components.