AT&T Bell Laboratories, Murray Hill, New Jersey

Reported here is a study of the transmission of magnetosheath hydromagnetic fluctuations with ¦ ~ 23 mHz and ¦ ~ 13 mHz through the magnetopause. The study involves measurements of the fluctuations inside the magnetosphere on the ISEE 2 spacecraft near the equator and on the ground near the boundary flux tube connecting with the spacecraft. The magnetic energy of the fluctuations inside the magnetopause is about 1% of those in the magnetosheath. This ratio is consistent with that expected for the transmission of fast-mode waves through a magnetopause with a tangential discontinuity. Just inside the magnetopause the fluctuations are right-hand elliptically polarized as measured both on the spacecraft and on the ground. About 10% of the near-magnetopause energy at 13 mHz is measured on the ground at L ~ 2.6. It is uncertain, from present theoretical concepts, how such high energy levels are produced so deep into the magnetosphere as a result of surface wave attenuation.

J. Geophys. Res., 94, No. A6, 6933-6939, 1989