AAS 204th Meeting, June 2004
Session 39 Solar Magnetic Fields and Activity
SPD Poster, Tuesday, June 1, 2004, 10:00am-7:00pm, Ballroom

[Previous] | [Session 39] | [Next]

[39.07] Solar Cycle Onsets

J. L. R. Saba (Lockheed Martin ATC & NASA/GSFC), G. L. Slater, K. T. Strong (Lockheed Martin ATC)

Previously, we have reported on a surprisingly rapid onset of Solar Cycle 23 in August/September 1997. To recapitulate:

Within two solar rotations, the integrated full-disk X-ray flux seen by the Yohkoh Soft X-ray Telescope (SXT) jumped from solar-minimum conditions to 50% of the total flux at solar maximum; magnetic data from both the SOHO Michelson Doppler Imager and the National Solar Observatory Vacuum Telescope at Kitt Peak showed factor of 2-3, step-function increases in the strong field (above 25 G) flux in both northern and southern hemispheres. There was a sea change in the natures of the active regions -- from sparse, compact, isolated, and short-lived regions of both old and new cycles to more, larger, more active, and longer-lived regions of the new cycle only, with large-scale connections with each other and the polar regions.

We examine previous cycles to see if this rapid onset is a standard feature, and, if so, whether the character is the same. We use cycle 23 correlations between SXT and GOES X-ray signatures, between MDI and KPNO magnetic data, and between the X-ray and magnetic fluxes, for this look back in time. This study may have implications for linking conditions in the convection zone with the solar cycle phenomenon.

This work is supported by NASA contracts NAG5-13261 (MDI), NAS8-00119 (SXT), and Lockheed Martin internal funding.

[Previous] | [Session 39] | [Next]

Bulletin of the American Astronomical Society, 36 #2
© YEAR. The American Astronomical Soceity.