Unstable O-mode generation in confined plasmas with multi-parametric gradient effects

In magnetically confined plasmas, gradients in density, temperature, and magnetic field generate low-frequency drift waves, which resonantly interact with plasma particles. In this investigation, we consider a nonlinear process due to which the energy of an accelerated particle may transfer to the O-mode present in the confined plasma system through a modulated field. This nonlinear process is based on a kinetic approach, analyzed using the Vlasov-Maxwell model system of equations. In this study, we derive the nonlinear dispersion relation for the O-mode incorporating gradient parameters and estimate its growth rate. Observational data from the Earth’s magnetosphere are used to analyze the influence of these gradient parameters and other plasma conditions. The results are relevant in predicting O-mode instabilities in inhomogeneous confined plasma systems, like Tokamaks, magnetospheric plasmas, etc.