34th Solar Physics Division Meeting, June 2003
Session 8 Helioseismology
Poster, Monday, June 16, 2003, 3:30-5:00pm, Mezzanine

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[8.05] Time-Series Analysis of Solar Neutrino Data: Evidence for Rieger-type Periodicities and their Interpretation as R-Modes

P.A. Sturrock (Stanford University)

Power-spectrum analysis of the Homestake and GALLEX-GNO radiochemical solar neutrino data has shown evidence of the effects of solar rotation and indications of two oscillations that are well known in solar physics: one at about 154 days period (the Rieger periodicity) and another at about 52 days period. We speculate that these periodicities, and another well known periodicity at about 77 days, are due to r-mode oscillations with spherical harmonic indices l = 3 and m = 1, 2, and 3. In the rotating frame, these would have frequencies fR/6, fR/3, and fR/2, where fR is the sidereal rotation rate where the waves are excited. We have combined power spectra formed from both neutrino datasets, and then tested the combined spectrum for the presence of peaks at four related frequencies: the above three r-mode frequencies, and the corresponding synodic frequency fR 1. In the range 0 20 y-1, we find a strong peak at 13.88 y-1 which falls in the rotation frequency range of the radiative zone. By applying the shuffle test, we find that the probability of obtaining by chance a peak this big or bigger in this range is less than 0.1%. This analysis suggests that Rieger-type periodicities are caused by r-mode oscillations in the radiative zone, and that these oscillations may lead to modulation of the solar neutrino flux, probably by the RSFP (Resonant Spin Flavor Precession) mechanism. This research was supported by the National Science Foundation.

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