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RESEARCH PRODUCT
Penumbral oscillations in Na D lines
E. MarcoW. Mattigsubject
PhysicsSunspotEvanescent waveOscillationPenumbraPhase (waves)Astronomy and AstrophysicsAstrophysicsSolar physicsSpectral lineSpace and Planetary ScienceAstrophysics::Solar and Stellar AstrophysicsCoherence (signal processing)Atomic physicsdescription
Penumbral oscillations were measured in two opposite parts in the penumbra of a spot, using photographic spectra of Na D lines. Power spectra of velocities show the presence of the 5-min oscillation with lowv rms. Coherence and phase analyses between the velocity fluctuations of the lines are also studied. The results seem to show that the 5-min oscillation is still surviving as a standing or evanescent wave at the height of formation of Na D lines.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1990-08-01 | Astrophysics and Space Science |