부산대학교 도서관

Dipolarization fronts (DFs), ion‐scale magnetic transients characterized by dramatic enhancement of northward magnetic field, have been documented as crucial energy transfer regions in the magnetosphere. DF‐driven energy transfer has hitherto been studied mainly in the laminar regime. Energy transfer driven by turbulent processes, however, remains unclear. Here we perform a comprehensive investigation of turbulent energy transfer (TET) developed at DFs, via using high‐cadence data from Magnetospheric Multiscale mission. We find that: (a) TET is equally governed by energy loads and generators, different from laminar energy transfer which is typically dominated by energy loads; (b) ion and electron currents play comparable roles in driving TET; (c) TET is positively correlated with local magnetic field strength and ion speed; (d) TET shows asymmetric global distributions along the dawn‐dusk direction. These features implicate that TET is primarily related to electromagnetic turbulence at electron‐ion hybrid scales. These new results, uncovering unique characteristics of DF‐driven TET, can deeply advance our understanding of energy budgets in the magnetosphere. Plain Language Summary: The sun constantly emits outward‐propagating plasma flows called solar wind. When arriving close to Earth, the solar wind interacts with Earth's internal, dipolar magnetic field, leading to formation of long, stretched magnetic field lines in the Earth's nightside, dubbed as magnetotail. The magnetotail hosts a variety of plasma structures which contribute to energy transport therein. Dipolarization fronts (DFs), characterized by sharp enhancement of northward component of magnetic field at ion scale, have been suggested as the leading boundaries of plasma jets (bursty bulk flows) in the magnetotail. They usually host the interaction between the jets and the ambient plasma. Hence, DFs have been suggested as the crucial regions in which intense energy transfer occurs. So far, it has been well documented that the DF‐driven energy transfer is closely related to large‐scale electric fields and ion currents, which are essentially laminar (i.e., direct‐current). Contributions from turbulent (i.e., alternating ‐current) fields and currents remain not well understood. In this study, we use high‐cadence data from NASA's Magnetospheric Multiscale mission to perform a comprehensive investigation of turbulent energy transfer (TET) developed at DFs, uncovering some important features. These results help better understand energy transport in the terrestrial magnetotail. Key Points: Turbulent energy transfer (TET) is equally governed by energy loads and generators, with comparable contributions from electron and ion currentsTET is positively correlated with local magnetic field strength and ion speedTET may be related to electromagnetic turbulence at electron‐ion hybrid scales [ABSTRACT FROM AUTHOR]