6 research outputs found
Power Spectrum Analysis of LMSU (Lomonosov Moscow State University) Nuclear Decay-Rate Data: Further Indication of r-Mode Oscillations in an Inner Solar Tachocline
This article presents a power-spectrum analysis of 2,350 measurements of the
Sr/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 to 3.98 year, 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. 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.Comment: 5 pages, 8 figures. v2 corrects three typographical errors on page 3,
including the missing list of r-modes in sec. 3, para
Magnetospheric response of two types in PSc geomagnetic pulsations to interaction with interplanetary shock waves
Using the June 22, 2015 event as an example, we present new data confirming the presence of a precursor of the sudden magnetic impulse caused by a powerful interplanetary shock wave (ISW). The precursor in the form of a train of oscillations (broadband pulse) with a falling frequency in the range 0.25÷11 Hz with a duration of ~20 s, which had a spectral resonance structure, was recorded globally by a network of induction magnetometers at 18:33:27 UT. No significant phase delays of the signals were detected in four frequency bands at widely spaced observatories. It is suggested that the impulse can be excited in the Earth – ionosphere waveguide by a pulsed electric field which occurs in the ionosphere due to the short-term impact of ISW on the magnetosphere
Solar Influence on Nuclear Decay Rates: Constraints from the MESSENGER Mission
We have analyzed Cs-137 decay data, obtained from a small sample onboard the
MESSENGER spacecraft en route to Mercury, with the aim of setting limits on a
possible correlation between nuclear decay rates and solar activity. Such a
correlation has been suggested recently on the basis of data from Mn-54 decay
during the solar flare of 13 December 2006, and by indications of an annual and
other periodic variations in the decay rates of Si-32, Cl-36, and Ra-226. Data
from five measurements of the Cs-137 count rate over a period of approximately
5.4 years have been fit to a formula which accounts for the usual exponential
decrease in count rate over time, along with the addition of a theoretical
solar contribution varying with MESSENGER-Sun separation. The indication of
solar influence is then characterized by a non-zero value of the calculated
parameter \xi, and we find \xi=(2.8+/-8.1)x10^{-3} for Cs-137. A simulation of
the increased data that can hypothetically be expected following Mercury orbit
insertion on 18 March 2011 suggests that the anticipated improvement in the
determination of \xi could reveal a non-zero value of \xi if present at a level
consistent with other data.Comment: Accepted for publication in Astrophysics and Space Science, 2011. 7
pages, 5 figures. Version 2 has corrected Figure 1, since Fig. 1 did not
appear correctly in Version