Electromagnetic effects on electrostatic modes in a magnetized plasma

The complete dispersion relation governing longitudinal and transverse waves in an infinite, homogeneous, magnetized plasma is discussed for arbitrary directions of wave propagation. Various forms suitable for computing modifications of the electrostatic dispersion relation arising from the coupling to transverse waves when ωpe ≳ ck, are compared. The modifications which arise for electrostatic ion gyroharmonic instabilities are determined in an ordering scheme appropriate for the important unstable modes of a mirror-confined thermonuclear plasma. The resultant effects on a number of electrostatic modes are discussed.