| At
the Sun's surface, sunspots are known to be dark, planet-sized regions of
intense magnetic fields. But what lies below? Using observations from the
Michelson Doppler Imager (MDI) instrument aboard the space-based SOHO observatory,
astronomers have derived this premier picture of the flow of material just
beneath a visible sunspot. |
|
The
MDI data indicate that immediately under the sunspot a strong inflowing
current exists, shown above by the dark arrows. This converging undertow
pulls near-surface material toward the spot and prevents the concentrated
magnetic fields from flying apart, like repelling poles of iron magnets.
Such a configuration appears to divert the normal flow of plasma bubbling
up from the solar interior, creating a self-sustaining sunspot. The MDI
instrument can explore the properties of the solar interior by detecting
motions produced by sound waves as they interact at the solar surface. |
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