Small-scale magnetic turbulence in the solar wind

Magnetic fluctuations in the solar wind follow nearly Kolmogorov's power law below the ion cyclotron frequency. Above this frequency, the observed steeper power law is believed to be a "dissipative range" of the solar wind turbulence. We investigate magnetic field fluctuations in a range lasting two decades above the ion cyclotron frequency by using the CLUSTER mission data. We conjecture that the low-frequency Alfvenic turbulence observed at large-scales, gives place to a kind of magneto-sonic turbulence, generated by a different nonlinear cascade and related to dispersive effects. Comparison by some numerical simulations are also presented.