Dynamics of the solar transition zone

Journal Article · Fri Dec 15 04:00:00 EST 1978 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/156691· OSTI ID:6199078

Bruner, Jr, E C

This paper reports on the analysis of time-resolved C IV line profiles arising from the solar transition zone. Objectives were twofold: to determine whether the 300 s photospheric oscillations penetrate to the transition zone, and to measure the rms velocity disturbance amplitude and its dependence upon solar activity. The data set consisted of 44 times sequences of 50 min average duration and included samples from study experiments of both active and quiet regions of the disk. Power-spectrum analysis of the time series of intensity and line position measurements showed at least one example of a well-developed 300 s oscillation. There was no evidence, however, for 300 s peaks in the average power spectra either in the quiet network or in active regions.The rms velocities were found to be about 2.3 km s/sup -/1 in active regions and 5.7 km s/sup -1/ in quiet regions. The suggested average value, allowing for the substantial statistical noise contribution to the quiet Sun data, is about 3 km s/sup -1/. The inferred energy flux, assuming energy transport by acoustic waves, is at most 1.6 x 10/sup 4/ ergs cm/sup -2/ s/sup -1/ for spatial scales greater than 15,000 km and periods in the range 100--1800 s. The acoustic-wave hypothesis apparently fails by at least one order of magnitude to provide the 2--6 x 10/sup 5/ ergs cm/sup -2/ s/sup -1/ thought to be required to replace coronal energy losses. The data are, however, consistent with heating mechanisms based on energy transport by magnetohydrodynamic waves.

• Research Organization: Lockheed Palo Alto Research Laboratory
• OSTI ID: 6199078
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 226:3; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
ENERGY TRANSFER
OSCILLATIONS
PHOTOSPHERE
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SOUND WAVES
SPECTRA
ULTRAVIOLET SPECTRA
WAVE PROPAGATION