Cyclotron instabilities of a two-component electron plasma

Abstract

A study is made of instability at frequencies close to the electron cyclotron frequencyΩ _B and its multiples, subject to the presence of two different groups of electrons. It is shown that a mixture of hot and cold electrons (Ω ²_ph ≪ Ω ²_pc ) in the region of frequenciesΩ ≈ sΩ _B, s≧2 can be unstable with respect to waves of the flute type (k _z=0) with maximum incrementγ _max ≈ (Ω _ph/Ω_pc).Ω _B, if there exists an interval of transversal velocitiesΝ _⊥ in which∂F/∂Ν _⊥>0. When the curvature of the magnetic field is taken into account, even waves withΩ ≈ Ω _B can be unstable in such a plasma. The effect of spatial inhomogeneity of the hot component on flute-type instability and on two-beam cyclotron instability is also examined.