  Unpulsed, high-energy emission from pulsar binaries can be attributed to the
interaction of a pulsar wind with that of a companion star. At the shock
between the outflows, particles carried away from the pulsar magnetosphere are
accelerated and radiate both in synchrotron and inverse Compton processes. This
emission constitutes a significant fraction of the pulsar spin-down luminosity.
It is not clear however, how the highly magnetized pulsar wind could convert
its mainly electromagnetic energy into the particles with such high efficiency.
Here we investigate a scenario in which a pulsar striped wind converts into a
strong electromagnetic wave before reaching the shock. This mode can be thought
of as a shock precursor that is able to accelerate particles to
ultrarelativistic energies at the expense of the electromagnetic energy it
carries. Radiation of the particles leads to damping of the wave. The
efficiency of this process depends on the physical conditions imposed by the
external medium. Two regimes can be distinguished: a high density one, where
the EM wave cannot be launched at all and the current sheets in the striped
wind are first compressed by an MHD shock and subsequently dissipate by
reconnection, and a low density one, where the wind can first convert into an
electromagnetic wave in the shock precursor, which then damps and merges into
the surroundings. Shocks in binary systems can transit from one regime to
another according to binary phase. We discuss possible observational
implications for these objects.
