ION Technical Content
In the Teeth of Cycle 23
| Abstract: | Solar Cycle 23 is now at its maximum. This time of highest solar activity is manifesting itself on two fronts. The Sun is producing episodic emissions -- both photons and plasma -- causing magnetic and ionospheric storms that can last from a few minutes to a few days. Simultaneously, and on a continuous, day-to-day basis, the solar output in the extreme ultraviolet (EUV) wavelengths is increasing by approximately a factor of four over what it was at the start of the cycle, raising the total electron content (TEC) of the ionosphere by a similar amount. The magnetic storm and solar flare events attest to the highly erratic nature of solar activity. Expectations were that the maximum phase of this cycle would be a time of strong solar flare and coronal mass ejection (CME) activity. Both of these events are occurring, and of late, the counts of flares and CMEs have been increasing. The regular, systematic increase in EUV has made the ionosphere more difficult for GPS to cope with on a day- to-day basis. This change in the Sun's output has caused both the peak value and the variability of the TEC to be problematic for some GPS applications. This so-called “background ionosphere” level has risen as the EUV has brightened. GPS now faces the strongest solar activity. Are we at the top of the activity curve -- in the teeth of the storm? How long will elevated activity levels persist? A summary of what has occurred to this point, and speculations on how Cycle 23 will play out, follow. |
| Published in: |
Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000) September 19 - 22, 2000 Salt Palace Convention Center Salt Lake City, UT |
| Pages: | 626 - 633 |
| Cite this article: | Kunches, Joseph M., "In the Teeth of Cycle 23," Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000), Salt Lake City, UT, September 2000, pp. 626-633. |
| Full Paper: |
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