Dynamic magnetic structure of large amplitude Alfvenic variations in the solar wind

Journal Article · Sat Mar 01 04:00:00 EST 1980 · Geophys. Res. Lett.; (United States)

DOI:https://doi.org/10.1029/GL007i003p00189· OSTI ID:5449938

Lichtensein, B R; Sonett, C P

The dynamic structure of large amplitude alfvenic disturbances of the interplanetary magnetic field (MF) is examined by transforming one-hour intervals of EXplorers 33 and 35 magnetometer data from the solar ecliptic coordinate system to a coordinate system defined by the principal axes of the variance matrix. Graphic displays of the rotated magnetometer data, in the form of linear time series for the field component in the direction of minimum variance and hodographs for the magnetic field vector component in the plane of maximum variance reveal order structure to field components which appear almost random when displayed as time series in the solar ecliptic coordiante system. When there is a well defined minimum variance direction, the component of the magnetic field in the plane normal to the direction of minimum variance tends to oscillate with constant magnitude so that the tip of the vector lies on a circular arc. However, the angular motion of the vector appears to be unstrained. This type of behavior for the IMF satisfies the necessary local conditions for plane large amplitude Alfven waves. Residual variability of the magnetic field in the direction of minimum variance may be due to the fully three-dimensional oscillations of the nearly plane waves or a small compressional component associated with fluctuations in the magnetic field magnitude. The different types of angular motion of the magnetic field component normal to the direction of minimmum variance may be indicative of the detailed conditions of the solar coronal plasma in the regions generating the Alfven waves, or some aspect of local generation.

• Research Organization: Lunar Planetary Laboratory, University of Arizona, Arizona 85721
• OSTI ID: 5449938
• Journal Information: Geophys. Res. Lett.; (United States), Journal Name: Geophys. Res. Lett.; (United States) Vol. 7:3; ISSN GPRLA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALFVEN WAVES
COORDINATES
DISTURBANCES
FLUID MECHANICS
HYDRODYNAMICS
HYDROMAGNETIC WAVES
INTERPLANETARY MAGNETIC FIELDS
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MAGNETOMETERS
MEASURING INSTRUMENTS
MECHANICS
MORPHOLOGY
SOLAR ACTIVITY
SOLAR CORONA
SOLAR WIND