The Radioactivity of Nuclei &Solar Oscillations: New Experiments

The experimental detection of the hidden periodicities in the activity of various radioactive sources which were observed by different instruments and which coincided with the period of the free oscillations of the Sun gave an impetus to the further research. The simultaneous recording of gamma rays from two radioactive sources revealed the elements of synchronism and the periods of solar oscillations as well as the phase delay for the different sources in the obtained time series. A neutrino detector has been designed and tested, the advanced schemes for neutrino detection are developed, and the impact of the neutrino source on the radioactive matter is explored. The search for the new principles for creating the emitters of neutrino beams is conducted.

Simultaneous detection of flare-associated kink oscillations and extreme-ultraviolet waves

Kink oscillations,which are frequently observed in coronal loops and prominences,are often accompanied by extreme-ultraviolet(EUV)waves.However,much more needs to be explored regarding the causal relationships between kink oscillations and EUV waves.In this article,we report the simultaneous detection of kink oscillations and EUV waves that are both associated with an X2.1 flare on 2023 March 03(SOL2023-03-03T17:39).The kink oscillations,which are almost perpendicular to the axes of loop-like structures,are observed in three coronal loops and one prominence.One short loop shows in-phase oscillation within the same period of 5.2 min at three positions.This oscillation could be triggered by the pushing of an expanding loop and interpreted as the standing kink wave.Time lags are found between the kink oscillations of the short loop and two long loops,suggesting that the kink wave travels in different loops.The kink oscillations of one long loop and the prominence are possibly driven by the disturbance of the coronal mass ejection(CME),and that of another long loop might be attributed to the interaction of the EUV wave.The onset time of the kink oscillation of the short loop is nearly same as the beginning of an EUV wave.This fact demonstrates that they are almost simultaneous.The EUV wave is most likely excited by the expanding loop structure and shows two components.The leading component is a fast coronal wave,and the trailing one could be due to the stretching magnetic field lines.

Non-homogeneous solar models with metal enriched envelopes

Solar models with enhancement of heavy elements in the convectiveenvelopes are investigated using the updated input physics. Unlike previous low-Z models that adopt quite low central metal abundance to considerably reduce neutrino fluxes, we investigate the effects of moderate enrichment of heavy elements in the solar convection zone on the solar structure and p-mode oscillations. It is found that the metal enriched models have less massive convection zones with deeper bottom boundaries, and their temperature profiles are systematically lower while the sound speed profiles are higher in the interior and lower in the envelope than that of the standard model. The contamination of heavy elements at different evolution phases is investigated, which results in little influence on the properties of the solar age models. The surface helium abundance is reduced considerably, and is able to approach the seismically determined value when the enhancement of heavy elements in the convection zone is carefully adjusted. The p-mode frequency patterns of our metal enriched models are systematically 10 μHz lower than those of the standard model, and are in better agreement with the results of observations.