Field Localization and associated Power Spectrum in Solar Wind

English Abstract:

Alfven waves are the normal modes of the plasma and have been observed in various space plasma regions and laboratory plasmas. Coupling of Alfven waves with other low frequency waves has got the far reaching research interest from decades. In the present case, we propose to study the nonlinear interaction between 3D-kinetic Alfvén wave (KAW) and ion acoustic wave (IAW). Authors have developed the set of dimensionless equations when pump KAW is perturbed by the low frequency ion acoustic wave present in the background and undergoes filamentation instability. Impact of the proposed interaction on the magnetic field coherent structures and spectrum is investigated. Numerical simulation of the coupled normalized dynamical equations, taking ponderomotive nonlinearity into account, has been performed using pseudo spectral method. Our results reveal Kolmogorov scaling followed by steeper scaling of power spectra. Relevance of present investigation for solar wind plasma has been discussed. Our presented model attempts to understand various features solar wind power spectrum which is reported in literature from the analysis of data available from CLUSTER mission [Sahraoui et al., 2009].

References:

 

[1] Evidence of a Cascade and Dissipation of Solar-Wind Turbulence at the Electron Gyroscale, Phys. Rev. Lett. 102, 231102, (2009)