P1.8
Do bursts of activity define the solar cycle and do they have forecast potential?
Julia L. R. Saba, Lockheed Martin Advanced Technology Center, Greenbelt, MD; and K. T. Strong
Solar cycle 23 began with a bang: a global outbreak of activity within two rotations. This was found first in the integrated solar X-ray flux but was produced by a surge in the emergence of strong-field magnetic flux, and mirrored in step-like features in most wavelengths and activity indicators examined, the major exception being the total solar irradiance. The outburst corresponded to a blossoming of interconnected, new-cycle structures, a marked change in the outer corona, and a suppression of old-cycle regions. A similar X-ray outburst heralded the onset of cycle 22, and proxy data for previous cycles indicate sudden onsets are the norm.
An abrupt onset to the solar cycle has important implications for the nature of the dynamo and/or flux transport mechanisms within the Sun, and led us to speculate that a cycle may have similar bursts of activity throughout. Quick-look analysis of cycle 23 and some previous cycles suggests they may be amenable to treatment as a superposition of global bursts with periods lasting 3-6 months. Magnetic and X-ray image data yield information on the location and the nature of the bursts that could be useful for forecasting activity on timescales of months, and may offer clues that presage the cycle onset by as much as a year.
Poster Session 1, Space Weather Posters
Monday, 21 January 2008, 2:30 PM-4:00 PM, Exhibit Hall B
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