Cross-scale nonlinear interaction and bifurcation in multi-scale turbulence of high-temperature plasmas

作者：T. Tokuzawa, T. Nasu, D. Nishimura, K. Ida, Mikirou Yoshinuma, T. Kobayashi, K. Tanaka, S. Inagaki, A. Fujisawa, I. Yamada, K. Itoh · 发表于：Communications Physics · 年份：2025 · DOI：10.1038/s42005-025-02245-4 · 被引用次数：2 · 研究领域：Magnetic confinement fusion research、Ionosphere and magnetosphere dynamics、Laser-Plasma Interactions and Diagnostics

The structural formation of magnetized high-temperature plasmas, which are ubiquitous in nature, is often controlled by turbulence. Such plasma turbulence is characterized by multiple scales and thus cross-scale nonlinear interactions are key to understanding its dynamics and structural formation. This is also the case for laboratory plasmas, for which multi-scale turbulence data are most abundant. The interactions of components on the meso- and ion-gyroradius (micro)-scales have been extensively studied. Here we report, the experimental discovery of the cross-scale nonlinear interactions between fluctuations at micro-scale and hyper-fine (HF)-scale (whose scale is about an electron gyroradius). Cross-scale bifurcation is found, in which micro-scale turbulence is suppressed, and the amplitude of HF-scale turbulence simultaneously increases. There is also an abrupt change in the isotropy of HF-scale components. We discuss a possible mechanisms in which nonlinear interactions, related to the weakening of the electric field generated by micro-scale turbulence, enhance HF-scale turbulence. Turbulence in magnetized high-temperature plasmas, crucial for both natural and laboratory settings, involves complex cross-scale interactions. Here, the authors experimentally uncover nonlinear interactions between micro- and hyper-fine scale fluctuations, revealing a bifurcation that suppresses micro-scale turbulence while amplifying hyper-fine scale turbulence, with significant implications ...