Solar-cycle variation of the sound-speed asphericity from GONG and MDI data 1995–2000期刊界 All Journals 搜尽天下杂志传播学术成果专业期刊搜索期刊信息化学术搜索

Solar-cycle variation of the sound-speed asphericity from GONG and MDI data 1995–2000

Authors:	H.M. Antia S. Basu F. Hill R. Howe R.W. Komm J. Schou

Affiliation:	¹Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India;²Astronomy Department, Yale University, PO Box 208101, New Haven, CT 06520-8101, USA;³National Solar Observatory, 950 N. Cherry Ave., PO Box 26732, Tucson, Arizona, 85726-6732, USA;⁴Hansen Experimental Physics Laboratory, HEPL Annex A201, Stanford University, Stanford, CA 94305-4085, USA

Abstract:	We study the variation of the frequency splitting coefficients describing the solar asphericity in both GONG and MDI data, and use these data to investigate temporal sound-speed variations as a function of both depth and latitude during the period 1995–2000 and a little beyond. The temporal variations in even splitting coefficients are found to be correlated to the corresponding component of magnetic flux at the solar surface. We confirm that the sound-speed variations associated with the surface magnetic field are superficial. Temporally averaged results show a significant excess in sound speed around and latitude of 60°.

Keywords:	Sun: interior Sun: oscillations