Structure and Oscillations in Quiescent Filaments from Observations in He I Wavelength 10830 A
Abstract
Observations of two quiescent filaments show oscillatory variations in Doppler shift and central intensity of the He I Solar 10830 Angstroms line. The oscillatory periods range from about 5 to 15 min. with dominant periods of 5, 9, and 16 min. The possibility that the oscillations are Alfven waves is discussed. The Doppler signals of the filament form fibril-like structures. The fibrils are all inclined at an angle of about 25 degrees to the long axis of the filament. The magnetic field has a similar orientation relative to the major direction of the filament, and the measured Doppler signals are apparently produced by motions along magnetic flux tubes threading the filament.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1991
- Accession Number
- ADA234406
Entities
People
- Oddbjorn Engvold
- Stephen L. Keil
- Yi Zhang
Organizations
- Phillips Laboratory