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Fantastic Voyage Inside the Sun (Animation)
July 18, 2002
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image: NASA / Walt Feimer, Max-Q Digital
This computer animation illustrates how emerging magnetic structures form areas of stormy solar activity, called active regions, on the Suns surface. Instead of one large tube-like magnetic structure that rises from deep inside the Sun, scientists found that active regions are made up of many relatively small magnetic structures (represented by white loops) emerging at adjacent locations.
Scientists analyzed sound-generated ripples on the Suns surface with a technique similar to a medical ultrasound. Because sound travels faster in solar regions with a strong magnetic field, they could construct a picture of the magnetic structures inside the Sun. It was the Michelson Doppler Imager (MDI) instrument on the Solar and Heliospheric Observatory (SOHO) that allowed the study.
Active regions are sites of fierce activity, generating explosions called solar flares and eruptions of electrified and magnetized gas (plasma) called Coronal Mass Ejections (CMEs). Scientists know this activity is driven by distorted magnetic fields that suddenly snap to a new, less energetic configuration, and that active regions are sites of strong magnetic fields. The dark blotches at the bases of the arches are sunspots, which are relatively cool, dark areas on the surface of the Sun that form when solar magnetic fields become concentrated.
"These discoveries are showing us that the Suns interior is much more complex and dynamic than we thought," said Prof. Philip Scherrer of Stanford University who is Principal Investigator of the SOHO/MDI project. "This emerging picture tells us that understanding violent solar activity, which is driven by turbulence within the Sun, will be more challenging."