Under A Sunspot
Explanation:
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.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
