论文标题
惠斯勒波作为在空间等离子体中收集磁孔的签名
Whistler Waves As a Signature of Converging Magnetic Holes in Space Plasmas
论文作者
论文摘要
磁孔是血浆结构，可将大量颗粒捕获到比周围环境中弱的磁场中。 NASA的磁层多尺度（MMS）任务的前所未有的高时间分辨率观察，使我们能够详细研究地球磁石中磁孔中的粒子动力学。我们通过响应磁孔的大规模演变而揭示了惠斯勒波的局部生成机理。随着磁孔的收敛，由于Betatron和费米效应的联合作用，一对孔中心附近形成了一对反流电子束。梁触发了略微散布的惠斯勒波的产生。我们的概念预测得到了我们的观察结果与任意线性等离子体求解器（ALP）的数值预测之间的显着共识的支持。我们的研究表明，波颗粒相互作用是空间和天体物理等离子体中磁孔进化的基础。
Magnetic holes are plasma structures that trap a large number of particles in a magnetic field that is weaker than the field in its surroundings. The unprecedented high time-resolution observations by NASA's Magnetospheric Multi-Scale (MMS) mission enable us to study the particle dynamics in magnetic holes in the Earth's magnetosheath in great detail. We reveal the local generation mechanism of whistler waves by a combination of Landau-resonant and cyclotron-resonant wave-particle interactions of electrons in response to the large-scale evolution of a magnetic hole. As the magnetic hole converges, a pair of counter-streaming electron beams form near the hole's center as a consequence of the combined action of betatron and Fermi effects. The beams trigger the generation of slightly-oblique whistler waves. Our conceptual prediction is supported by a remarkable agreement between our observations and numerical predictions from the Arbitrary Linear Plasma Solver (ALPS). Our study shows that wave-particle interactions are fundamental to the evolution of magnetic holes in space and astrophysical plasmas.
