Japanese Researchers Achieve World's Finest Reproduction of Inner Sun

Tokyo, April 11 (Jiji Press)--A team of Japanese researchers said Friday they have succeeded in reproducing the thermal convection mechanism in the sun's interior with the highest-ever level of precision, using Japan's K supercomputer. The achievement was announced in the online edition of The Astrophysical Journal of the United States. The researchers include Takaaki Yokoyama, associate professor at the University of Tokyo's Graduate School of Science, and Hideyuki Hotta, a former student at the same graduate school who currently serves as a research fellow of the Japan Society for the Promotion of Science. The computation method devised by the researchers and the high performance of the K enabled a level of reproduction some six times more precise that that achieved by a U.S. team in 2008. Over a cycle of about 11 years, increases and decreases in the number of sunspots, with strong magnetic fields on the surface and comparatively lower temperatures, have a long-term impact on the Earth's climate. "The latest achievement is a step forward for clarifying the mechanism and predicting changes in the activities of the sun," Hotta said. Heat from the center of the sun at ultrahigh temperatures caused by nuclear fusion is conveyed to the outside convection zone of plasma gas, comprising hydrogen and helium. The movement of electrified gas in the convection zone is seen developing magnetic fields and creating sunspots on the surface in a complicated mechanism. Theoretical studies about the emergence of sunspots have been slow due to the imprecise reproduction of the thermal convection. In the simulation with the K, the researchers found that magnetic fields are amplified at the bottom of the convection zone and small-scale thermal convection near the surface of the sun goes deeper into the sun to cause turbulence. END