  We present a study of the acceleration of electrons at a perpendicular shock
that propagates through a turbulent magnetic field. The energization process of
electrons is investigated by utilizing a combination of hybrid (kinetic ions
and fluid electron) simulations and test-particle electron simulations. In this
method, the motions of the test-particle electrons are numerically integrated
in the time-dependent electric and magnetic fields generated by two-dimensional
hybrid simulations. We show that large-scale magnetic fluctuations effect
electrons in a number of ways and lead to efficient and rapid energization at
the shock front. Since the electrons mainly follow along magnetic lines of
force, the large-scale braiding of field lines in space allows the fast-moving
electrons to interact with the shock front and get accelerated multiple times.
Ripples in the shock front occurring at various scales will also contribute to
the acceleration by mirroring the electrons. Our calculation shows that this
process favors electron acceleration at perpendicular shocks. The acceleration
efficiency is critically dependent on the turbulence amplitude and coherence
length. We also discuss the implication of this study for solar energetic
particles (SEPs) by comparing the acceleration of electrons with that of
protons. Their correlation indicates that perpendicular shocks play an
important role in SEP events.
