arXiv subjects

Eunseok Hwang

Publications and source records attributed to Eunseok Hwang.

5 recordsLinked to original sources

arXiv2026

The Non-thermal Energy Window for Laser-Driven Nuclear Reactions

Laser-driven nuclear reactions proceed in non-equilibrium plasma conditions, producing ion energy distributions that are not Maxwellian. Nevertheless, fusion yields in such experiments are often interpreted using effective thermal descriptions based on the conventional Gamow window. In this work, we develop an analytical framework for evaluating nuclear reaction rates for non-thermal ions accelerated by the Target Normal Sheath Acceleration (TNSA) mechanism. Using a self-similar plasma expansion model, we derive a closed form expression for an effective reaction energy window and the corresponding fusion reactivity. The resulting effective energies differ systematically from those predicted by thermal models, indicating limitations of interpretations based on the conventional Gamow window in laser-driven environments. This framework provides a quantitative basis for analyzing fusion yields and for designing laser-driven nuclear experiments.

physics.plasm-ph↗

arXiv2025

Upper Limit of Fusion Reactivity in Laser-Driven $p+{^{11}{\rm B}}$ Reaction

We explore the averaged fusion reactivity of the $p+{^{11}{\rm B}}$ reaction in tabletop laser experiments using a plasma expansion model. We investigate the energy distribution of proton beams accelerated by lasers as a function of electron temperature $T_e$ and the dimensionless acceleration time $ω_{pi} t_{\rm acc}$, where $ω_{pi}$ is the ion plasma frequency. By combining these distributions with the fusion cross-section, we identify the optimal conditions that maximize the fusion reactivity, with $\left\langle σv \right\rangle = 8.12 \times 10^{-16}\,{\rm cm^3/s}$ at $k_B T_e = 10.0\,{\rm MeV}$ and $ω_{pi} t_{\rm acc} = 0.503$. These findings suggest that an upper limit exists for the fusion reactivity achievable in laser-driven $p+{^{11}{\rm B}}$ fusion experiments, even under optimized conditions.

physics.plasm-ph↗

arXiv2023

Revisiting the Gamow Factor of Reactions on Light Nuclei

This study provides an improved understanding of the penetration probabilities (PPs) in nuclear reactions of light nuclei by correcting the assumptions used in the conventional Gamow factor. The Gamow factor effectively describes the PP in nuclear reactions based on two assumptions: low particle energy than the Coulomb barrier and neglecting the dependence of nuclear interaction potential. However, we find that the assumptions are not valid for light nuclei. As a result of a calculation that excludes the assumptions, we obtain the PP that depends on the nuclear interaction potential depth for the light nuclei. For the potential depth fitted by the experimental fusion cross-section, we present that PPs of light nuclei (D+D, D+T, D+$^3$He, p+D, p+$^6$Li, and p+$^7$Li) become higher than the conventional one near the Coulomb barrier. We also discuss the implications of the modified PP, such as changes in the Gamow peak energy, which determine the measurement of the energy range of the nuclear cross-section in experiments, and the electron screening effect.

nucl-th↗

arXiv2022

Effects of electromagnetic fluctuations in plasmas on solar neutrino fluxes

We explore the effects of electromagnetic (EM) fluctuations in plasmas on solar neutrino fluxes exploiting the fluctuation-dissipation theorem. We find that the EM spectrum in the solar core is enhanced by the EM fluctuations due to the high density of the Sun, which increases the radiation energy density and pressure. By the EM fluctuations involving the modified radiation formula, the central temperature decreases when the central pressure of the Sun is fixed. With a help of the empirical relation between central temperature and neutrino fluxes deduced from the numerical solar models, we present the change in each of the solar neutrino fluxes by the EM fluctuations. We also discuss the enhanced radiation pressure and energy density by the EM fluctuations for other astronomical objects.

astro-ph.SR↗

arXiv2021

Dynamical Screening Effects on Big Bang Nucleosynthesis

A moving ion in plasma creates a deformed electric potential depending on the ion velocity, which leads to the distinct screening effect compared to the standard static Salpeter formula. In this paper, adopting the test charge method, we explore the dynamical screening effects on big bang nucleosynthesis (BBN). We find that the high temperature in the early universe causes the ion velocity to be faster than the solar condition so that the electric potential is effectively polarized. However, the low density of background plasma components significantly suppresses the dynamical screening effects on thermonuclear reaction rates during the BBN epoch. We compare our results with several thermonuclear reaction rates for solar fusion considering the dynamical screening effects. Also, we discuss the additional plasma properties in other astrophysical sites for the possible expansion from the present calculation in the future.

nucl-th↗