Growing electrostatic modes in the isothermal pair plasma of the pulsar magnetosphere

It is shown that a strongly magnetized isothermal pair plasma near the surface of a pulsar supports low-frequency (in comparison to electron cyclotron frequency) toroidal electrostatic plasma modes in the equatorial region. Physically, the thermal pressure coupled with the magnetic pressure creates the low frequency oscillations which may grow for particular case of inhomogeneities of the equilibrium magnetic field and the pair plasma density.