Inertial Alfvén wave localization and turbulent spectrum

The localization of pump inertial Alfvén wave (IAW) in low β plasmas (β ≪ m_e/ m_i) has been investigated by developing a model based on weak IAW and finite amplitude background density fluctuations. When IAW is perturbed by these fluctuations which are in the form of magnetosonic and ion acoustic waves, its phase velocity gets modified and IAW breaks up into localized structures of very high intensity. Numerical simulation has been carried out to analyze the localized structures and magnetic fluctuation spectrum of pump IAW. We have also developed a simplified model to understand the physical insight into evolution pattern of IAW. Results obtained from simulation reveal that turbulent spectrum up to k_⊥λ_e ≈ 1 follows Kolmogorov power law. Furthermore, at shorter wavelengths, dispersion starts and spectrum steepens with power law index ∼ - 3.8. Energy transport to smaller length scales through this mechanism may be accountable for the observed parallel electron heating in low β plasmas. Results obtained from the numerical simulation are consistent with the observations of various spacecraft like FAST and Hawkeye.