Cross‐scale coupling‐induced intermittency near interplanetary shocks

Abstract

Several approaches exist to address the problem of intermittency in solar wind turbulence. The traditional explanation based on spectral transfer of energy between separated scales through sequential steps within a cascade can elucidate scalings and intermittent emergence of small‐scale dissipative structures. A recent point of view connects intermittency mainly with the occurrence of discontinuities and interaction of flux tube‐like coherent structures. In this paper we analyze the interrelationship between skewness and kurtosis near interplanetary shocks. On the basis of a comparison of our results with the behavior of skewness and kurtosis in laboratory experiments and numerical simulations we show that large‐scale boundaries and/or scalar gradient fields imposed on solar wind turbulence can lead to a local increase of small‐scale intermittency via direct coupling between separated scales. As each scenario is supported by experiments, they represent a complementary way of looking at intermittency.