Direct Measurement of the Solar-Wind Taylor Microscale using MMS Turbulence Campaign Data

摘要: Using the novel Magnetospheric Multiscale (MMS) mission data accumulated during 2019 MMS Solar Wind Turbulence Campaign, we calculate Taylor microscale $(\lambda_{\mathrm{T}})$ of turbulent magnetic field in solar wind. The represents onset dissipative processes classical turbulence theory. An accurate estimation scale from spacecraft is, however, usually difficult due to low time cadence, effect decorrelation, and other factors. Previous reports were based either entirely on frozen-in approximation, which conflates dependence, or that obtained using multiple datasets, introduces sample-to-sample variation plasma parameters, where inter-spacecraft distance larger than present study. unique configuration linear formation with logarithmic spacing 4 spacecraft, campaign, enables a direct evaluation $\lambda_{\mathrm{T}}$ single dataset, independent approximation. A value $\lambda_{\mathrm{T}} \approx 7000 \, \mathrm{km}$ is obtained, about 3 times previous estimates.