Small-scale flux ropes (SFRs) are common in the interplanetary environment. However, previous identification procedures generally discard SFRs with medium and high Alfvnicity, which are thought to be Alfvnic waves or Alfvnic structures. This paper first identifies an SFR event with medium Alfvnicity in the inner heliosphere (at ∼0.2 au) using Parker Solar Probe measurements. We find Alfvnic waves that arise inside SFR based on high correlations between the magnetic field and velocity fluctuations. We also observe quasi-monochromatic electromagnetic waves with frequencies f that are usually larger than the local proton cyclotron frequency at the leading and trailing edges of this SFR. These waves are well explained by the outward-propagating ion-cyclotron waves, which have wave frequencies ∼0.03–0.3 Hz and wavelengths ∼60–2000 km in the plasma frame. Moreover, we show that the power spectral density of the magnetic field in SFR middle region follows the power-law distribution, where the spectral index changes from −1.5 (f ≲ 1 Hz) to −3.3 (f ≳ 1 Hz). These findings would motivate developing an automated program to identify SFRs with medium and high Alfvnicity from Alfvnic waves/structures.

小型通量绳（SFR）在行星际环境中很常见。但是，以前的识别程序通常会丢弃具有中等和高Alfvnicity的SFR，这些SFR被认为是Alfvnic波或Alfvnic结构。本文首先使用帕克太阳探测器测量结果确定了内部日光层中的Alfnicnity（约为0.2 au）的SFR事件。我们基于磁场和速度波动之间的高度相关性，发现在SFR内部产生的Alfvnic波。我们还观察到频率为f的准单色电磁波通常大于该SFR前沿和后沿的局部质子回旋频率。这些波可以通过向外传播的离子回旋波来很好地解释，这些波在等离子体框架中的波频率约为0.03-0.3 Hz，波长约为60-2000 km。此外，我们表明，在SFR中间区域中的磁场的功率谱密度遵循幂律分布，其中从-1.5频谱指数的变化（˚F ≲1赫兹）至-3.3（˚F ≳1赫兹）。这些发现将激励开发一个自动化程序，以从Alfvnic波/结构中识别出中，高Alfvnicity的SFR。