Journal ArticleDOI
Dynamic variations at the base of the solar convection zone
R. Howe,Jørgen Christensen-Dalsgaard,Frank Hill,Rudolf Komm,R. M. Larsen,Jesper Schou,Michael Thompson,Juri Toomre +7 more
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Changes in the rotation of the sun near the base of its convective envelope are detected, including a prominent variation with a period of 1.3 years at low latitudes, which may generate the 22-year cycles of magnetic activity.Abstract:
We have detected changes in the rotation of the sun near the base of its convective envelope, including a prominent variation with a period of 1.3 years at low latitudes. Such helioseismic probing of the deep solar interior has been enabled by nearly continuous observation of its oscillation modes with two complementary experiments. Inversion of the global-mode frequency splittings reveals that the largest temporal changes in the angular velocity Ω are of the order of 6 nanohertz and occur above and below the tachocline that separates the sun's differentially rotating convection zone (outer 30% by radius) from the nearly uniformly rotating deeper radiative interior beneath. Such changes are most pronounced near the equator and at high latitudes and are a substantial fraction of the average 30-nanohertz difference in Ω with radius across the tachocline at the equator. The results indicate variations of rotation close to the presumed site of the solar dynamo, which may generate the 22-year cycles of magnetic activity.read more
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Cosmic ray measurements at high cutoff rigidity site - Preliminarily results
TL;DR: In 2007, King Abdulaziz University, Jeddah (21.5o N; 39.2o E; 14.8 GV), Saudi Arabia, installed a single channel muon detector for monitoring and studying the variations of the cosmic ray (CR) muons as discussed by the authors .
Journal ArticleDOI
Variations of helioseismic parameters due to magnetic field generated by a flux transport model
TL;DR: In this paper, the authors reconstructed one-dimensional solar models by assimilating magnetic field generated by an established dynamo and examined their influences on the structural variables, and showed that magnetic fields generated by the dynamo is able to cause noticeable change of the sound speed profile at the base of the convective zone during a solar cycle.
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Journal ArticleDOI
Abundances of the elements: Meteoritic and solar
Edward Anders,Nicolas Grevesse +1 more
TL;DR: In this article, new abundance tables have been compiled for C1 chondrites and the solar photosphere and corona, based on a critical review of the literature to mid-1988.
Journal ArticleDOI
The Solar Oscillations Investigation - Michelson Doppler Imager
Philip H. Scherrer,R. S. Bogart,R. I. Bush,J. T. Hoeksema,Alexander G. Kosovichev,Jesper Schou,W. Rosenberg,L. Springer,T. D. Tarbell,A. M. Title,C. J. Wolfson,I. Zayer +11 more
TL;DR: The Michelson Doppler Imager (MDI) as mentioned in this paper was used to probe the interior of the Sun by measuring the photospheric manifestations of solar oscillations, revealing the static and dynamic properties of the convection zone and core.
Book ChapterDOI
The Solar Oscillations Investigation — Michelson Doppler Imager
Philip H. Scherrer,R. S. Bogart,R. I. Bush,J. T. Hoeksema,Alexander G. Kosovichev,Jesper Schou,W. Rosenberg,L. Springer,T. D. Tarbell,A. M. Title,C. J. Wolfson,I. Zayer +11 more
TL;DR: The Solar Oscillations Investigation (SOI) as mentioned in this paper uses the Michelson Doppler Imager (MDI) instrument to probe the interior of the Sun by measuring the photospheric manifestations of solar oscillations.
Journal ArticleDOI
Helioseismic Studies of Differential Rotation in the Solar Envelope by the Solar Oscillations Investigation Using the Michelson Doppler Imager
Jesper Schou,H. M. Antia,Sarbani Basu,R. S. Bogart,R. I. Bush,S. M. Chitre,Joergen Christensen-Dalsgaard,M. Di Mauro,W. A. Dziembowski,Antonio Eff-Darwich,Douglas Gough,Deborah A. Haber,J. T. Hoeksema,R. Howe,S. G. Korzennik,Alexander G. Kosovichev,R. M. Larsen,R. M. Larsen,Frank P. Pijpers,Philip H. Scherrer,Takashi Sekii,Theodore D. Tarbell,Alan M. Title,Michael Thompson,Juri Toomre +24 more
TL;DR: In this article, the authors report on joint helioseismic analyses of solar rotation in the convection zone and in the outer part of the radiative core using the Michelson Doppler Imager (MDI) on the Solar and Heliospheric Observatory (SOHO) spacecraft.
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