CISM

SOHO image animation (57k)
images from SOHO-EIT

The Solar Magnetic Field

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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