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

中文翻译：

---

使用 MMS 湍流运动数据直接测量太阳风泰勒微尺度

使用在 2019 年 MMS 太阳风湍流运动期间积累的新型磁层多尺度 (MMS) 任务数据，我们计算了太阳风中湍流磁场的泰勒微尺度 $(\lambda_{\mathrm{T}})$。泰勒微尺度代表了经典湍流理论中耗散过程的开始。然而，由于低时间节奏、时间去相关的影响和其他因素，从航天器数据准确估计泰勒尺度通常很困难。以前的报告要么完全基于泰勒冻结近似，它混淆了时间依赖性，要么使用多个数据集获得，这引入了等离子体参数的样本间变化，或者航天器间距离大于当前学习。在活动期间，4 个 MMS 航天器具有对数间距的线性编队的独特配置使得可以从单个数据集直接评估 $\lambda_{\mathrm{T}}$，独立于泰勒冻结近似。得到了 $\lambda_{\mathrm{T}} \approx 7000 \, \mathrm{km}$ 的值，比之前的估计大了大约 3 倍。