Plasma mixing as a cause of solar wind magnetic field variations

Abstract

In the present paper, we have studied the effect of plasma mixing on the small-scale field configurations. We have employed theoretical models and numerical simulations to describe magnetic field structures formed by the mixing motion of the interplanetary plasma. The small-scale magnetic fluctuations share properties with waves and with turbulence as well. It is shown that plasma mixing can account for both wave-like and turbulence-like behavior. Mixing can also explain the formation and the dominance of the so-called 2D fluctuations. Four-point measurements provide a new tool for the experimental investigation of the field configurations. Our effort was to identify the effect of plasma mixing. In a slow laminar mixing flow sheet-like structures are formed everywhere in the plasma. The existence of these kind of structures has been tested using the magnetometer data of the four Cluster spacecraft. Our results suggest that plasma mixing plays a significant role in the formation of the small-scale magnetic fluctuations of the solar wind. Our results support that the 2D component dominates the magnetic fluctuations.