Upstream Pc3-4 waves: Experimental evidence of propagation to the nightside plasmapause/plasmatrough

作者：Ponomarenko P V^*; Walters C L; St Maurice J P

来源：Geophysical Research Letters, 2010, 37: L22102.

DOI：10.1029/2010GL045416

Compressional magnetohydrodynamic (MHD) waves in the Pc3-4 frequency range (similar or equal to 10-50 mHz) are generally believed to be generated upstream of the Earth's bow-shock in reflected proton beams. Inside the closed field-line geometry, these waves are conventionally considered to be a dayside phenomenon. However, recent studies suggest that some of the nighttime Pc4 pulsations may in fact have an upstream origin. In this letter, we report synchronous variations of the Pc3-4 spectra near post-dawn cusp and nightside plasmapause/plasmatrough as observed by HF radar and ground magnetometers. The measured Pc3-4 frequency closely follows that of the upstream waves theoretically predicted based on the dynamics of the interplanetary magnetic field, which presents the most convincing evidence to date of upstream-generated Pc3-4 waves propagating to the nightside magnetosphere in the closed field-line geometry. We conclude the letter with a brief discussion of a possible propagation scenario. Citation: Ponomarenko, P. V., C. L. Waters, and J.-P. St-Maurice (2010), Upstream Pc3-4 waves: Experimental evidence of propagation to the nightside plasmapause/plasmatrough, Geophys. Res. Lett., 37, L22102, doi: 10.1029/2010GL045416.

• 出版日期2010-11-16