  Density inhomogeneities are ubiquitous in space and astrophysical plasmas, in
particular at contact boundaries between different media. They often correspond
to regions that exhibits strong dynamics on a wide range of spatial and
temporal scales. Indeed, density inhomogeneities are a source of free energy
that can drive various instabilities such as, for instance, the
lower-hybrid-drift instability which in turn transfers energy to the particles
through wave-particle interactions and eventually heat the plasma. We aim at
quantifying the efficiency of the lower-hybrid-drift instability to accelerate
and/or heat electrons parallel to the ambient magnetic field. We combine two
complementary methods: full-kinetic and quasilinear models. We report
self-consistent evidence of electron acceleration driven by the development of
the lower-hybrid-drift instability using 3D-3V full-kinetic numerical
simulations. The efficiency of the observed acceleration cannot be explained by
standard quasilinear theory. For this reason, we develop an extended
quasilinear model able to quantitatively predict the interaction between
lower-hybrid fluctuations and electrons on long time scales, now in agreement
with full-kinetic simulations results. Finally, we apply this new, extended
quasilinear model to a specific inhomogeneous space plasma boundary: the
magnetopause of Mercury, and we discuss our quantitative predictions of
electron acceleration in support to future BepiColombo observations.
