Observation of an inertial-range energy cascade within a reconnection jet in the Earth's magnetotail

Abstract

The Earth's magnetotail region provides a unique environment for the study of plasma turbulence. We investigate the turbulence developed in an exhaust produced by magnetic reconnection in the terrestrial magnetotail region. Magnetic and velocity spectra show broad-band fluctuations corresponding to the inertial range, with Kolmorogov scaling of −5/3, indicative of a well-developed turbulent cascade. We examine the mixed, third-order structure functions, and obtain a linear scaling in the inertial range. This linear scaling of the third-order structure functions implies a scale-invariant cascade of energy through the inertial range. A Politano-Pouquet third-order analysis gives an estimate of the incompressive energy transfer rate of ∼107 J kg−1 s−1. This is four orders of magnitude higher than the values typically measured in the 1-au solar wind, suggesting that the turbulence cascade plays an important role as a pathway of energy dissipation during reconnection events in the tail region.