NTRS - NASA Technical Reports Server

Back to Results
Elsaesser variable analysis of fluctuations in the ion foreshock and undisturbed solar windMagnetohydrodynamics (MHD) fluctuations in the solar wind have been investigated previously by use of Elsaesser variables. In this paper, we present a comparison of the spectra of Elsaesser variables in the undisturbed solar wind at 1 AU and in the ion foreshock in front of the Earth. Both observations take place under relatively strong solar wind flow speed conditions (approximately equal 600 km/s). In the undisturbed solar wind we find that outward propagating Alfven waves dominate, as reported by other observers. In the ion foreshock the situation is more complex, with neither outward nor inward propagation dominating over the entire range investigated (1-10 mHz). Measurements of the Poynting vectors associated with the fluctuations are consistent with the Elsaesser variable analysis. These results generally support interpretations of the Elsaesser variables which have been made based strictly on solar wind data and provide additional insight into the nature of the ion foreshock turbulence.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Labelle, James (Dartmouth College, Hanover, NH United States)
Treumann, Rudolf A. (Max-Planck-Institut fuer extraterrestrische Physik Garching, Germany)
Marsch, Eckart (Max-Planck-Institut fuer Aeronomie Katlenburg-Lindau, Germany)
Date Acquired
August 16, 2013
Publication Date
January 1, 1994
Publication Information
Publication: Journal of Geophysical Research
Volume: 99
Issue: A1
ISSN: 0148-0227
Subject Category
Funding Number(s)
Distribution Limits