Propagation directions of hydromagnetic waves in interplanetary space: Pioneer' 10 and 11
Abstract
The real and imaginary parts of spectral matrices of magnetic field fluctuations near 4 and 5 AU are used separately to generate estimates of hydromagnetic wave normal directions over the frequency range 10-5 to 10-2 Hz in the spacecraft frame. Both procedures suggest the predominance of the Alfvén mode over the fast and slow MHD modes among transverse magnetic field perturbations. Both procedures also show that the Alfvén mode is more common among transverse perturbations at 4 AU than a 5 AU. We develop statistical techniques for estimating uncertainties in computed wave normal directions and conclude that the real parts of the spectral matrices are more useful than the imaginary parts in specifying wave normals at times of magnetic quiet in the solar wind near 4 and 5 AU.
- Publication:
-
Journal of Geophysical Research
- Pub Date:
- August 1980
- DOI:
- 10.1029/JA085iA08p04283
- Bibcode:
- 1980JGR....85.4283P
- Keywords:
-
- Interplanetary Space;
- Magnetohydrodynamic Waves;
- Solar Wind;
- Wave Propagation;
- Complex Numbers;
- Direction;
- Pioneer 10 Space Probe;
- Pioneer 11 Space Probe;
- Propagation Modes;
- Vector Analysis