美国西南研究所Burch J. L.小组报道了空间合唱发射过程中的场-粒子能量转移。相关论文于2025年1月22日发表在《自然》杂志上。

据悉，合唱波是太空中自然产生的最强电磁辐射之一，可以产生对人类和卫星有害的辐射。虽然合唱波已经引起了极大的兴趣，并被深入研究了几十年，但它们的产生和演变仍然存在很大的争议。

与传统的期望相反，合唱波是由行星磁偶极子场控制的，研究人员报告了在没有磁偶极子影响的地球中性层中，重复的、上升音调的合唱波的观测结果。利用美国宇航局MMS任务的高节奏数据，研究人员展示了波场和波内三维电子分布的超快测量，这为波相空间中chortem -电子相互作用和电子空穴的发展提供了证据。

研究人员发现这些波与与波磁场反平行的共振电流有关，正如非线性波理论所预测的那样。研究团队估计了波内部的非线性场-粒子能量传递，发现波从局部热电子中提取能量，符合由不稳定性分析得出的波的正增长率。他们的观测可能有助于解决长期以来关于合唱发射的争议，并有助于了解在空间和天体物理环境中观测到的能量传输。

附：英文原文

Title: Field–particle energy transfer during chorus emissions in space

Author: Liu, C. M., Zhao, B. N., Cao, J. B., Pollock, C. J., Russell, C. T., Liu, Y. Y., Xing, X. N., Linqvist, P. A., Burch, J. L.

Issue&Volume: 2025-01-22

Abstract: Chorus waves are some of the strongest electromagnetic emissions naturally occurring in space and can cause radiation that is hazardous to humans and satellites1,2,3. Although chorus waves have attracted extreme interest and been intensively studied for decades4,5,6,7, their generation and evolution remain highly debated7. Here, in contrast to the conventional expectation that chorus waves are governed by planetary magnetic dipolar fields5,7, we report observations of repetitive, rising-tone chorus waves in the terrestrial neutral sheet, where the effects of the magnetic dipole are absent. Using high-cadence data from NASA’s MMS mission, we present ultrafast measurements of the wave fields and three-dimensional electron distributions within the waves, which provides evidence for chorus–electron interactions and the development of electron holes in the wave phase space. We found that the waves are associated with resonant currents antiparallel to the wave magnetic field, as predicted by nonlinear wave theory. We estimated the nonlinear field–particle energy transfer inside the waves, finding that the waves extract energy from local thermal electrons, in line with the positive growth rate of the waves derived from an instability analysis. Our observations may help to resolve long-standing controversies regarding chorus emissions and in gaining an understanding of the energy transport observed in space and astrophysical environments.

DOI: 10.1038/s41586-024-08402-z

Source: https://www.nature.com/articles/s41586-024-08402-z