Oscillating two stream instability of a plasma wave in a negative ion containing plasma with hot and cold positive ions

Abstract

An oscillating two-stream instability (OTSI) is investigated in plasma, which has hot and cold positive ions, negative ions, and the electrons. For this, a long wavelength plasma wave is considered to be driven by two copropagating lasers with frequencies ω_L1 and ω_L2, such that their difference is almost equal to the electron plasma frequency ω_p. In the present mechanism, this plasma beat wave (ω_b, k_b) is taken to grow in amplitude, so that it becomes susceptible to the OTSI and produces a low frequency electrostatic mode (ω, k), and two shorter wavelength Langmuir wave sidebands (ω₁, k₁) and (ω₂, k₂) with ω₁ = ω − ω_b, ω₂ = ω + ω_b, k₁ = k − k_b, and k₂ = k + k_b in the plasma. The effects of charge number Z, mass, temperature, and density of the ions are studied on the growth rate of the instability, and the amplitudes and phases of the sideband waves generated during the OTSI. It is found that the effects of charge number and mass of the ions are significant on the instability.