2025ApJ...994...80L

Turbulence in the interstellar medium (ISM) plays an important role in many physical processes, including forming stars and shaping complex ISM structures. In this work, we investigate the H I turbulence properties of the Small Magellanic Cloud (SMC) to reveal what physical mechanisms drive the turbulence and at what scales. Using high-resolution H I data from the Galactic ASKAP survey and multipoint structure functions (SFs), we perform a statistical analysis of H I turbulence in 34 subregions of the SMC. The two-point SFs tend to show a linear trend, and their slope values are relatively uniform across the SMC, suggesting that large-scale structures exist and are dominant in the two-point SFs. On the other hand, seven-point SFs enable us to probe small-scale turbulence by removing large-scale fluctuations, which is difficult to achieve with the two-point SFs. In the seven-point SFs, we find break features at scales of 34-84 pc, with a median scale of ∼50 pc. This result indicates the presence of small-scale turbulence fluctuations in the SMC and quantifies their scale. In addition, we find strong correlations between the slope values of the seven-point SFs and stellar-feedback-related quantities (e.g., Hα intensity, the number of young stellar objects, and the number of H I shells), suggesting that stellar feedback may affect the small-scale turbulence properties of the H I gas in the SMC. Lastly, the estimated sonic Mach numbers across the SMC are subsonic, which is consistent with the fact that the H I gas of the SMC primarily consists of a warm neutral medium.