NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Is the magnetosphere a lens for MHD waves?A viewpoint of the magnetosphere as a lens for MHD waves is presented. Using a simple model of the variation of the Alfven speed as proportional to the local magnetic value given by the Earth's dipole field and that due to the magnetopause currents represented by a current loop, it is found that the near-Earth magnetotail, in the range 8-16 R(sub E), is the focus of the magnetospheric lens. This location is found to be quite insensitive to a wide variation of parameters. By using simple diffraction theory analysis it is found that the focal region extends about 1 R(sub E) about the neutral sheet in the north-south plane and 0.2 - 0.5 R(sub E) along the Sun-Earth line. Compressive MHD waves carried by the solar wind or created by the interaction of the wind with the magnetopause can be amplified by a factor of about 100 in the focal region and this has potentially important implications to substorm activity.
Document ID
19950047200
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Papadopoulos, K.
(Univ. of Maryland, College Park, MD United States)
Sharma, A. S.
(Univ. of Maryland, College Park, MD United States)
Valdivia, J. A.
(Univ. of Maryland, College Park, MD United States)
Date Acquired
August 16, 2013
Publication Date
December 23, 1993
Publication Information
Publication: Geophysical Research Letters
Volume: 20
Issue: 24
ISSN: 0094-8276
Subject Category
Geophysics
Accession Number
95A78799
Funding Number(s)
CONTRACT_GRANT: NAG5-1101
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available