EE 350 RADIOSCIENCE SEMINAR
Professor Umran Inan
Date: Wednesday, January 16, 2002
Time: 4:15 PM; Refreshments at 4:00 PM
Time Series Analysis of the Solar Neutrino Flux - Is
There a Signal in the Noise?
Prof. Peter Sturrock
Applied Physics and Physics
Several experiments have been collecting solar neutrino data for many years. Most of the available
data comes from radiochemical experiments, which produce an estimate of the neutrino flux every
three or four weeks. In each "run," only a few neutrinos are captured. As a result, the
measurements are both coarse and noisy. Attempts to correlate these measurements with sunspot data,
etc., have been unconvincing.
Most forms of radiation from the Sun exhibit a strong oscillation with a period of order 27 days
due to solar rotation. In this seminar, we shall describe our search for similar oscillations in
the solar neutrino flux. On the face of it, this is not a very promising exercise, since we are
looking for oscillations with periods comparable with the sampling interval and, indeed, with the
integration interval. We shall argue that, despite these very real difficulties, it is still
possible to search for a solar-rotation signal by means of time-series analysis. We shall present
the present evidence that the neutrino flux is indeed modulated by solar rotation, and we shall
discuss, very briefly, the significance of this result.