摘要： AbstractAccording to theory, foreshock ultra‐low frequency (ULF) waves are allowed to propagate mainly along the ambient magnetic field; however, waves obliquely propagating at a noticeably large angle can be easily observed. Although the mechanism of wave refraction was proposed to resolve the disagreement, doubts on the application of wave refraction to oblique propagation still remain. With the Time History of Events and Macroscale Interactions during Substorms (THEMIS) data, we examine the dependence of the oblique propagation of the ULF waves on solar wind parameters. The distributions of the oblique propagation angle θkB2 are spread out over a wide range of the solar wind parameters. From the mechanism of wave refraction, we derive the θkB2 as a function of the upstream propagation angle θkB1, the ratio of solar wind speed to upstream and downstream wave phase speed <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgra50225-math-0001.gif" xlink:title="urn:x-wiley:21699380:media:jgra50225:jgra50225-math-0001"/>, and the angle between the interplanetary magnetic field (IMF) and solar wind velocity θBV. Both of the prediction and the observation show the irrelevance of the wave frequency, the sense of polarization, the strength of the IMF, and solar wind speed to the oblique propagation. We find that the prediction from wave refraction is in good agreement with the observation, especially along the track of prediction lines with the same θkB1 and <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgra50225-math-0002.gif" xlink:title="urn:x-wiley:21699380:media:jgra50225:jgra50225-math-0002"/>. 其他題名： J. Geophys. Res. Space Physics 出版者： Washington: Blackwell Publishing Ltd 出版日期： 2013-07 出處： Journal of Geophysical Research: Space Physics, 2013-07, Vol.118 (7), p.4151-4160 資源來源： Wiley Online Library 版權： 2013. American Geophysical Union. All Rights Reserved. 識別號： ISSN: 2169-9380 識別號： ISSN: 2169-9402 識別號： EISSN: 2169-9402 識別號： DOI: 10.1002/jgra.50225
