Chiba University announced that it was the first in the world to elucidate the mechanism that creates the "solar cycle of 11 years" by the ultra-high resolution calculation made possible by the supercomputer "K computer".This result was published in the American scientific journal "Science" by an international research group including Hideyuki Hotta, a specially appointed assistant professor at the Graduate School of Science, Chiba University, and Hiroaki Yokoyama, an associate professor at the Graduate School of Science, the University of Tokyo.
The sun has a strong magnetic field region called sunspot, and the number of sunspots fluctuates every 11 years depending on the activity of the sun.However, the mechanism has not been clarified and it was called "the oldest mystery of the sun".It is also suggested that the earth was cold in the 1600s, during the period of about 70 years when there were no sunspots, and it is urgent to clarify this mystery when considering the global environment.
The magnetic field is thought to be generated by turbulence inside the Sun, but the process of creating an orderly large-scale magnetic field that creates an 11-year cycle has been elucidated from the highly chaotic turbulence. not.This time, the research group has developed a calculation method "sound velocity suppression method" that reduces the load. Ultra-high resolution calculation by "K computer" was performed.
Until now, it has been said that "the higher the turbulence, the larger the magnetic field cannot be created."Even with this calculation, up to a certain resolution, the results were as expected so far.However, in the ultra-high resolution realized this time, the small-scale magnetic field generation became very active, exceeding the energy of the small-scale turbulent motion.This refers to the state where "the turbulence is no longer high despite the high resolution".As a result, even in highly turbulent situations such as the sun, only ordered large-scale flows are allowed, and large-scale magnetic fields have been successfully developed.
This mechanism is supposed to work in the actual sun, and it can be said that the basic and important mechanism for solving the problem of the solar cycle has been clarified.In the future, it is expected that the oldest mystery of the sun will be solved in earnest by confirming the details of the theory through observations centered on satellites.