Lee E, Parks G K, Wilber M, Lin N
Space Sciences Laboratory, University of California, Berkeley, California 94720, USA.
Phys Rev Lett. 2009 Jul 17;103(3):031101. doi: 10.1103/PhysRevLett.103.031101. Epub 2009 Jul 16.
We report first in situ multispacecraft observations of nonlinear steepening of compressional pulses in the solar wind upstream of Earth's bow shock. The magnetic field of a compressional pulse formed at the upstream edge of density holes is shown to suddenly break and steepen into a shocklike structure. During the early phase of development thermalization of ions is insignificant. Substantial thermalization of ions occurs as gyrating ions are observed at the steepened edge. These observations indicate that the mechanisms causing the dissipation of magnetic fields (currents) and ions are different in the early phase of shock development.
我们首次报告了在地球弓形激波上游太阳风中压缩脉冲非线性陡化的多航天器原位观测结果。在密度空洞上游边缘形成的压缩脉冲的磁场被显示突然破裂并陡化为类似激波的结构。在发展的早期阶段，离子的热化不显著。在陡化边缘观察到回旋离子时，离子发生了大量热化。这些观测结果表明，在激波发展的早期阶段，导致磁场（电流）和离子耗散的机制是不同的。
