An Observational Search for Large-Scale Organization of Five-Minute Oscillations on the Sun.
Abstract
The large-scale solar velocity field has been measured over an aperture of radius 0.8 R on 121 days between April and Sept., 1976. Measurements are made in the line FeI 5123.730A, employing a velocity subtraction technique similar to that of Severny et al. (1976). Comparisons of the amplitude and frequency of the five-minute resonant oscillations with the geomagnetic C9 index and magnetic sector boundaries show no evidence of any relationship between the oscillations and coronal holes or sector structure. The average period measured for the five-minute oscillation is 312.0 plus or minus 0.9 sec, which is longer than the average 296.1 plus or minus 1.3 sec period originally reported by Noyes and Leighton (1963) from measurements in the line CaI 6103. The average amplitude is 2.0 m/s, which agrees reasonably with the 2.4 m/s value reported by Fossat and Ricort (1975). This amplitude is larger than might have been expected from an extrapolation of the work of Tanenbaum et al. (1969) to a large aperture, and is evidence of a large horizontal wavelength for the oscillations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1977
- Accession Number
- ADA047842
Entities
People
- John M. Wilcox
- Phil H. Dittmer
- Philip Scherrer
Organizations
- Stanford University