MODEL OF INTERMITTENCY IN MAGNETOHYDRODYNAMIC TURBULENCE

We extend to the magnetohydrodynamic (MHD) case a recent model of inte rmittency due to She and Leveque [Phys. Rev. Lett. 72, 336 (1994)]. Th e model that we develop in the framework of the Iroshnikov-Kraichnan t heory of MHD turbulence depends on two parameters that are linked to a nomalous scaling laws of dissipative structures when their characteris tic scale l --> 0. A brief comparison with published data stemming fro m spacecraft observations within the solar wind [L. Burlaga, J. Geophy s. Res. 96, 5847 (1991)] shows that it is a workable model and that wi thin the framework of the model, dissipative structures in MHD turbule nce are sheetlike, as observed in recent numerical simulations in thre e dimensions at moderate Reynolds numbers.