Here Comes the Sun

by J. William Bell

Simulations on NCSA's SGI Origin2000 array are giving researchers a new understanding of convection and magnetic flux near the solar surface.

Large-scale features of the sun have been known for centuries. Galileo and his contemporaries began observing and recording the existence of sunspots not long after the invention of the telescope in the early 1600s. And ancient Aztec creation describe a sun god with a pockmarked face, giving us what may be the first image of a sun with a mottled complexion. Sunspots, some of the most noticeable features on the sun's face, measure as large as 50,000 miles in diameter, survive several months, and result from magnetic activity deep within the sun.

A face, however, is more than just its most distinguishing features. The upper regions of the sun create and are littered with smaller but no less significant details. Patches of hot gas called granules create bright patches about 1,200 miles across that last approximately ten minutes and are surrounded by lanes of cool, darker gas. Other tiny pores and bright spots leave their minute marks. Even magnetic fields too small to be observed from earth contribute to the sun's countenance.

Robert Stein, a physics and astronomy professor at Michigan State University, and Aake Nordlund of Copenhagen University Observatory in Denmark are using NCSA's SGI Origin2000 supercomputer to simulate the processes behind the sun's smaller-scale features. Creating massive models of portions of the sun, their research team is focused on understanding convection and magnetic flux near the solar surface.

Access Online | Posted 11-21-2000

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