Multifractal structure of the dissipation field of intensity fluctuations in the solar photosphere

We investigate the scaling properties of the photospheric intensity field, using images acquired at the THEMIS telescope with the Italian Panoramic Monochromator. After calculating the power spectrum of the continuum intensity fluctuations, we analyze the scaling laws of the dissipation field obtained from the intensity fluctuations, in analogy with the dissipation of passive scalar fluctuations in turbulent fluids. Using the multifractal formalism, we show that the dissipation is intermittent and that it is characterized by stronger singularities in the higher photosphere than in the lower photosphere.