  I argue that the problem of electromagnetically driven electron-positron
cascades in magnetospheres of neutron stars must be addressed starting from
first principles. I describe a general numerical algorithm for doing
self-consistent kinetic simulations of electron-positron cascades - wherein
particle acceleration, pair creation and screening of the electric field are
calculated simultaneously - and apply it to model the Ruderman and Sutherland
cascade in one dimension. I find that pair creation is quite regular and
quasi-periodic. In each cycle a blob of ultrarelativistic electron-positron
plasma is generated, it propagates into the magnetosphere leaving a tail of
less relativistic plasma behind, and the next discharge occurs when this mildly
relativistic plasma leaves the polar cap. A short burst of pair formation is
followed by a longer quiet phase when accelerating electric field is screened
and no pairs are produced. Some of freshly injected electron-positrons pairs
get trapped in plasma oscillations creating a population of low energy
particles. The cascade easily adjusts to the current density required by the
pulsar magnetosphere by reversing some of the low energy particles. Each
discharge generates a strong coherent superluminal electrostatic wave, which
may be relevant for the problem of pulsar radioemission.
