Fractal dissipation of small-scale magnetic fluctuations in solar wind turbulence as seen by CLUSTER

A robust multiscale analysis of high‐frequency magnetic field measurements from the Cluster spacecraft is presented using complimentary measurements from the magnetometer and search‐coil instruments; in a stationary interval of fast ambient solar wind. We show a surprising and novel result: that for time‐scales smaller than the ion‐gyro period the magnetic field fluctuations exhibit non‐Gaussian monoscaling i.e. are globally scale invariant and can be characterized by a single scaling exponent and thus a single universal scaling function for the probability density. This presents new questions, as well as theoretical constraints, for determining how magnetic turbulent energy is dissipated in collisionless plasmas.