  We present particle-in-cell (PIC) simulations of minority energetic protons
in deuterium plasmas, which demonstrate a collective instability responsible
for emission near the lower hybrid frequency and its harmonics. The simulations
capture the lower hybrid drift instability in a regime relevant to tokamak
fusion plasmas, and show further that the excited electromagnetic fields
collectively and collisionlessly couple free energy from the protons to
directed electron motion. This results in an asymmetric tail antiparallel to
the magnetic field. We focus on obliquely propagating modes under conditions
approximating the outer mid-plane edge in a large tokamak, through which there
pass confined centrally born fusion products on banana orbits that have large
radial excursions. A fully self-consistent electromagnetic relativistic PIC
code representing all vector field quantities and particle velocities in three
dimensions as functions of a single spatial dimension is used to model this
situation, by evolving the initial antiparallel travelling ring-beam
distribution of 3MeV protons in a background 10keV Maxwellian deuterium plasma
with realistic ion-electron mass ratio. The simulations thus demonstrate a key
building block of alpha channelling scenarios for burning fusion plasmas in
tokamaks.
