Power Spectrum Analysis of LMSU (Lomonosov Moscow State University) Nuclear Decay-Rate Data: Further Indication of r-Mode Oscillations in an Inner Solar Tachocline

TL;DR

This study analyzes nuclear decay-rate data from LMSU, revealing power spectrum peaks indicative of r-mode oscillations in the solar interior, suggesting a connection between decay rates and solar dynamics.

Contribution

It provides evidence of r-mode oscillations in the solar interior through decay-rate power spectrum analysis, proposing an inner tachocline as the oscillation region.

Findings

Detection of low-frequency peaks similar to solar diameter oscillations

Identification of r-mode oscillations with a sidereal rotation frequency of 12.08 year$^{-1}$

Evidence supporting oscillations occurring in an inner solar tachocline

Abstract

This article presents a power-spectrum analysis of 2,350 measurements of the $^{90}$Sr/$^{90}$Y decay process acquired over the interval 4 August 2002 to 6 February 2009 at the Lomonosov Moscow State University (LMSU). As we have found for other long sequences of decay measurements, the power spectrum is dominated by a very strong annual oscillation. However, we also find a set of low-frequency peaks, ranging from 0.26 year$^{-1}$ to 3.98 year$^{-1}$, which are very similar to an array of peaks in a power spectrum formed from Mt Wilson solar diameter measurements. The Mt Wilson measurements have been interpreted in terms of r-mode oscillations in a region where the sidereal rotation frequency is 12.08 year$^{-1}$. We find that the LMSU measurements may also be attributed to the same type of r-mode oscillations in a solar region with the same sidereal rotation frequency. We propose that these oscillations occur in an inner tachocline that separates the radiative zone from a more slowly rotating solar core.