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Solar wind turbulent spectra and role of hall effect: A case study

Abstract:

Turbulent fluctuations within solar wind spectrum follows nearly Kolmogorov's power law spectrum f<sup>-5/3</sup> below the ion cyclotron frequency f<inf>ci</inf>. Above this frequency, the observed steeper power law is believed to be a 'dissipative range' of the solar wind turbulence. In this paper we analyze magnetic field fluctuations measured onboard CLUSTER, lasting two decades above f<inf>ci</inf>. Well defined power law and a strong increase of intermittency with frequency in this range indicates that turbulence cannot be characterized by a 'dissipative range'. Rather we conjecture that above f<inf>ci</inf> the turbulence is generated by a different nonlinear cascade where, using Hall MHD formulation in the incompressible limit, magnetic power follows f<sup>-7/3</sup>-law.