arXiv subjects

P. A. Sturrock

Publications and source records attributed to P. A. Sturrock.

39 records · Page 3Linked to original sources

arXiv1999

Rotational Signature and Possible R-Mode Signature in the GALLEX Solar Neutrino Data

Recent analysis of the Homestake data indicates that the solar neutrino flux contains a periodic variation that may be attributed to rotational modulation occurring deep in the solar interior, either in the tachocline or in the radiative zone. This paper presents an analysis of GALLEX data that yields supporting evidence of this rotational modulation at the 0.1% significance level. The depth of modulation inferred from the rotational signature is large enough to explain the neutrino deficit. The Rieger 157-day periodicity, first discovered in solar gamma-ray flares, is present also in Homestake data. A related oscillation with period 52 days is found in the GALLEX data. The relationship of these periods to the rotational period inferred from neutrino data suggests that they are due to r-mode oscillations.

astro-ph↗

arXiv1996

An Apparent Periodicity in the Gallex, Homestake and Kamiokande Neutrino Data

In order to explore a recent proposal that the solar core may contain a component that varies periodically with a period in the range 21.0 - 22.4 days, due either to rotation or to some form of oscillation, we have examined the time series formed from measurements of the solar neutrino flux by means of the GALLEX, Homestake and Kamiokande experiments. Direct Fourier transform analysis of the Homestake data shows that the most prominent peak in the entire spectrum (examined down to 5 days period) is found at a frequency of approximately 17.2 y-1 corresponding to a period of approximately 21.3 days. According to the "shuffle test," the probability of finding this large a peak in the prescribed search band is about 0.03%, if it is assumed that there is no correlation between count rate and time. The GALLEX and Kamiokande data are examined in a way that searches for similarity in the shapes of the two spectra in sliding windows in frequency. We find that the "spectral correlation measure" peaks at 17.2 y-1, and the shuffle test indicates that the probability of finding this large a peak at a specified frequency is 2%, if it is again assumed that for each time series there is no correlation between count rate and time. The combined significance estimate is of order 1 part in 105 that the results are due to chance, on the assumption that there is no real structure to the count-rate time series.

astro-ph↗

arXiv1996

A Conjecture Concerning the Rieger and Quasi-Biennial Solar Periodicities

It has been established that the Rieger periodicity of approximately 153 days is part of a complex of periodicities, all multiples of a basic period of approximately 25.5 days. However, it has not been clear why the sixth subharmonic of this periodicity should be preferentially manifested. We here note that if the Sun contains two rotating elements, with different periods and different axes, a special situation will arise if the two periods have a lowest common multiple, for in this case the relative configuration of the two rotators would repeat exactly at that (LCM) period. This chain of thought leads us to suspect that the Sun contains a second rotating element with rotational period in the range 21 - 22.5 days.

astro-ph↗