  New plasma mechanism for the generation of toroidal magnetic field in the
magnetosphere of Crab pulsar is presented. It is based on the development of
two-stream instability in the relativistic electron-positron plasma of the
pulsar magnetosphere. In particular, pulsar magnetosphere relativistic plasma
is penetrated by ultrarelativistic electron beam and two-stream instability
develops, as a result of which toroidal magnetic field is generated.
