The evolving solar magnetic field is
the ultimate cause of virtually all
space weather storms. It also
determines parameters important to
calm space weather, such as the
level of ionizing solar Extreme
UltraViolet emission and galactic
cosmic ray access to 1 AU.
Observations of the Sun's
magnetic field are our primary
requirement for building physical
models of solar/interplanetary
space weather.
The figures show positive
(outward/light) and negative
(inward/dark) magnetic fields on
the Sun obtained with the
Stanford/Lockheed MDI instrument
on the ESA/NASA SOHO
spacecraft. Examples shown are a
sequence of full disk images
showing a solar rotation in January
1998; the 9-day disk passage of an
emerging southern-hemisphere
active region observed during the
same time interval ; and a 2-year
sequence showing the rising phase
of the current solar cycle, frames
are global synoptic maps
assembled from full disk images
(bottom).
Stanford also acquires daily
full-disk observations at much
lower spatial resolution at the
Wilcox Solar Observatory on the
campus. Other solar magnetic field
data are available on-line from the
Kitt Peak National Observatory, the
GONG network, and elsewhere.
SOLIS ground-based telescopes
will eventually provide vector
magnetic field information.
Click to the images to the left to view the corresponding animation.
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