Photoelectric observations of chromospheric sunspot oscillations. II. Propagation chracteristics

Journal Article · Wed Feb 15 04:00:00 EST 1984 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/161758· OSTI ID:6883358

Lites, B W

Measurements of oscillations in umbrae and penumbrae using the line pairs (Ca II lambda8498--lambda8542) and (Fe I lambda5434--Ca II lambda8498)= are presented for seven sunspots and 11 observing runs. In the umbral chromosphere, the observations reported here, taken with other measurements of umbral oscillations, suggest that the oscillations are upward propagating acoustic (or slow mode) disturbances, and that they become nonlinear and develop into shock waves in the upper layers. They cause a significant increase in the radiative output of the umbral chromosphere, indicating the possibility of nonthermal heating at these levels. On the basis of this picture, umbral chromosphere, indicating the possibility of nonthermal heating at these levels. On the basis of this picture, umbral chromospheres have a greater physical extent in height than predicted by umbral models with coronal pressures greater than those found in the quiet Sun. Oscillations are present in the outer regions of penumbrae with frequencies and phase relationships that suggest the possibility of magneto-gravity waves.

• Research Organization: Sacramento Peak National Observatory
• OSTI ID: 6883358
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 277:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
CHROMOSPHERE
OSCILLATIONS
SOLAR ACTIVITY
SOLAR ATMOSPHERE
STARSPOTS
SUNSPOTS