A statistical analysis of NaI D1profile fluctuations at the center of the solar disk

✍ Scribed by Frank N. Edmonds; Jin-Chung Hsu

• Publisher: Springer
• Year: 1983
• Tongue: English
• Weight: 827 KB
• Volume: 83
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00148276

✦ Synopsis

Three radial-velocity fluctuation arrays V(A2, Y) and line-formation fluctuation arrays L(A2, Y),where A2 is wavelength displacement from the center ofNal D 1 and Y is displacement on the Sun's surface along the spectrograph slit, were obtained from Sacramento Peak Observatory spectrograms. The variations of these line profile fluctuations are qualitatively described. The RMSv's, coherences, and power spectra shapes for V(A2, Y) fluctuations are examined at different A2 with the corresponding effective heights of formation calculated with Mein weighting functions.

Results include: (a) possible anticorrelation between continuum fluctuations and those near line center; (b) RMS~Cr)'s, which are root-mean-square values of the radial velocity corrected for instrumental and . atmospheric blurring, are large (1.5 to 4.0 km s -1) primarily due to large corrections for atmospheric blurring; (c)RMS~ or) minima at effective heights of formation above 350 km suggest penetration of granulation velocities into the upper photosphere; (d) very rough determinations of RMS~t~ which are additionally corrected for line-of-sight averaging, range from around 5 km s-~ in the low chromosphere to a sharp minimum <0.5 km s -~ located in the upper photosphere; (e)power spectra shapes reflect decreasing average fluctuation scales above the temperature minimum (possibly high-frequency oscillations) and in the low and middle photosphere (possibly penetration of granulation); and (f) RMS~Cr)'s and average fluctuation scales suggest changes in the resolvable velocity field occurring near the temperature minimum.