2020 Fiscal Year Annual Research Report
The primordial magnetic field fluctuations, its evolution and the impact on Big-bang nucleosynthesis
| Project/Area Number |
19J22167
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| Research Institution | National Astronomical Observatory of Japan |
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Principal Investigator |
LUO Yudong 国立天文台, 科学研究部, 特別研究員(PD)
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| Project Period (FY) |
2019-04-25 – 2022-03-31
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| Keywords | r-process |
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| Outline of Annual Research Achievements |
In this year, I estimated the screening potential as well as the changes in weak interaction rates at high field, it is found that high fields can result in the increased beta-decay rates as the electron and positron spectra are dominated by Landau levels. The effects studied here are evaluated in a simple r-process model. We found that the explosive nucleosynthesis of r-process elements could finally provide an observational signal for such a strong magnetic field through the screening effect on the weak electron-capture rates affected by Landau quantization theoretically. This work is published on the Astrophysical Journal.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
This year, I extended my previous study to the strongly magnetized plasma. The screening potential could be much enhanced there. I also attended an international collaboration to study the Thomas-Fermi length inside the magnetohydrodynamical-Jet supernovae. Such an experience could benefit for the future development of my research to communicate with other researchers.
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| Strategy for Future Research Activity |
I will continue my study on the magnetized degenerate astrophysical plasma. I apply a relativistic Hartree self-consistent field method to calculate the screening potential and applied a profile from a 15 solar mass progenitor in order to evaluate the electron-capture rates of iron group nuclei 54Fe and 70Zn. I find that the screening potential in the high field is enhanced compared with the previous study. If the field is high enough and only the lowest Landau level is allowed, I find two orders of magnitude reduction in the electron capture rates in the high-density region. Such deviations of the 54Fe and 70Zn electron capture rates are essential since these two isotopes determine the neutron richness of the progenitor model as well as the iron core mass, which are crucial for supernovae explosion calculation. The reduction of electron capture rates of heavy nuclei under strongly magnetized degenerated plasma could also potentially deviate the neutrino absorption rate and the neutrino emission spectrum. Currently, I am preparing for the submission of the manuscript.
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