论文标题
解释泰勒假设之外的太阳风湍流
Interpreting solar wind turbulent spectra beyond Taylor's Hypothesis
论文作者
论文摘要
在本文中，我们采用了Bourouaine和Perez（2019）（BP19）最近提出的一种方法，以解释泰勒近似（TA）以外的太阳能湍流功率谱。使用\ emph {helios}的航天器数据在0.6 au附近测量湍流功率光谱。我们使用BP19中提出的模型来重现抗肺动物alfvénic$ e（k_ \ perp）$的反肺alfvénic在等离子体框架中的波动（其中$ k_ \ perp $是field-perpendicular apperpendicular vavenumber）从相应的测量频率频率$ p p _ {采样角$θ_b$，这是局部磁场和采样方向之间的角度。这里$ω=2πf$和$ f $是时间信号的频率。有趣的是，我们发现，对于所有相应的测量频率频谱$ p _ {\ rm sc}（ω，θ_b）$复制的现场 - 末端功率谱$ e（k_ \ perp）是相同的，并且独立于考虑的采样角$θ_b$。这一发现与分析的湍流具有强大且高度各向异性的事实是一致的。 \ ll k_ \ perp $（其中$ k_ \ | $是现场并行vavenumber）。此外，对于此特定时间信号，我们发现常用的TA仍然近似有效，其重要区别是，每个角频率$ω$都会扩大$ k_ \ perp $。可以在BP19中提出的方法的背景下进行描述。
In this paper we apply a methodology, recently proposed by Bourouaine and Perez (2019) (BP19), to interpret solar-wind turbulent power spectra beyond Taylor approximation (TA). The turbulent power spectra were measured using \emph{Helios} spacecraft data near 0.6 au. We use the model proposed in BP19 to reproduce the field-perpendicular power spectrum $E(k_\perp)$ of anti-sunward Alfvénic fluctuations in the plasma frame (where $k_\perp$ is the field-perpendicular wavenumber) from the corresponding measured frequency power spectrum $P_{\rm sc}(ω,θ_b)$ along the sampling angle $θ_b$, which is the angle between the local magnetic field and the sampling direction. Here $ω=2πf$ and $f$ is the frequency of the time signal. Interestingly enough, we found that for all corresponding measured frequency power spectrum $P_{\rm sc}(ω,θ_b)$ the reproduced field-perpendicular power spectrum $E(k_\perp)$ is the same and independent of the considered sampling angle $θ_b$. This finding is consistent with the fact that the analyzed turbulence is strong and highly anisotropic with $k_\| \ll k_\perp$ (where $k_\|$ is the field-parallel wavenumber). Furthermore, for this specific time signal we found that the commonly used TA is still approximately valid with the important difference that a broadening in $k_\perp$ for each angular frequency $ω$ is present. This broadening can be described in the context of the methodology proposed in BP19.
