Click for next page ( 2

The National Academies of Sciences, Engineering, and Medicine
500 Fifth St. N.W. | Washington, D.C. 20001

Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement

Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 1

OCR for page 1
 EXTENDED SUMMARY Genesis of a major space storm. On October 28, 2003, a large sunspot group in the Sun’s southern hemisphere (upper left) erupted, producing an intense x-ray flare (upper right) and a large, fast “halo” coronal mass ejection (CME). Within less than an hour of CME lift-off/flare eruption, solar energetic particles (SEPs), accelerated by the shock wave preceding the CME, began arriving at Earth, causing a polar cap absorption event and initiating ozone- destroying chemistry in the middle atmosphere over the poles. The SEP event was still in progress the following day, when the CME slammed into Earth’s magnetic field, triggering a powerful geomagnetic storm. The geomagnetic field was recovering when, late on October 30, a second CME, launched from the same active region as the first, arrived, unleashing another intense magnetic storm. All images were obtained with instruments on the Solar and Heliospheric Observatory (SOHO). Clockwise from the upper left: Michelson Doppler Imager (MDI) white light image of the photosphere; Extreme-ultraviolet Imaging Telescope (EIT) image of coronal Fe XII emissions; Large Angle and Spectrographic Corona (LASCO) C3 coronagraph image, showing “snow” caused by solar energetic particle bombardment; and a LASCO C2 near-Sun image of the halo CME. (Images courtesy of NASA/ESA.)