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Detailed Reference Information |
Lopez, R.E., Baker, D.N. and Allen, J. (2004). Sun unleashes Halloween storm. Eos, Transactions American Geophysical Union 85: doi: 10.1029/2004EO110002. issn: 0096-3941. |
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It is supposed to be a quiet time on the Sun, as we head toward solar minimum. At the beginning of October, it looked that way, as only a few small sunspots were visible. Then, sunspot group 484 came around the limb of the Sun on 18 October. By 23 October, when 484 was located right on the Earth-Sun line, this huge group covered 1.7% of the solar disk. At the far edge of the Sun, another massive sunspot group, 486, was just coming into the field of view. And late on the 26th, a third group, 488, emerged from the interior of the Sun just to the north of 486 (Figure 1). With this sudden increase in sunspots came a series of solar flares. The most powerful, X-class, have an integrated power (1.0--8.0 Angstroms) greater than 0.0001 W/m2. They can produce radio blackouts and damage space-based systems due to energetic protons. The first of the X-class flares occurred on 19 October, producing a category R3 radio blackout on the National Oceanographic and Atmospheric Administration (NOAA) space weather scale. On the 23rd, another flare registering between X4 and X5 was observed. This was followed by a series of smaller M- and X-class flares. |
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Abstract |
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Keywords
Solar Physics, Astrophysics, and Astronomy, Flares, Magnetospheric Physics, Storms and substorms |
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Journal
Eos, Transactions American Geophysical Union |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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