LLNLの研究者が、核融合反応におけるイオンの振る舞いが異なることを観測(LLNL researchers observe that ions behave differently in fusion reactions)


2022-11-14 ローレンスリバモア国立研究所(LLNL)



燃焼プラズマにおける超熱的なイオン分布の証拠 Evidence for suprathermal ion distribution in burning plasmas

E. P. Hartouni,A. S. Moore,A. J. Crilly,B. D. Appelbe,P. A. Amendt,K. L. Baker,D. T. Casey,D. S. Clark,T. Döppner,M. J. Eckart,J. E. Field,M. Gatu-Johnson,G. P. Grim,R. Hatarik,J. Jeet,S. M. Kerr,J. Kilkenny,A. L. Kritcher,K. D. Meaney,J. L. Milovich,D. H. Munro,R. C. Nora,A. E. Pak,J. E. Ralph,H. F. Robey,J. S. Ross,D. J. Schlossberg,S. M. Sepke,B. K. Spears,C. V. Young & A. B. Zylstra
Nature Physics  Published:14 November 2022

拡張データ 図 1


At the National Ignition Facility, inertial confinement fusion experiments aim to burn and ignite a hydrogen plasma to generate a net source of energy through the fusion of deuterium and tritium ions. The energy deposited by α-particles released from the deuterium–tritium fusion reaction plays the central role in heating the fuel to achieve a sustained thermonuclear burn. In the hydrodynamic picture, α-heating increases the temperature of the plasma, leading to increased reactivity because the mean ion kinetic energy increases. Therefore, the ion temperature is related to the mean ion kinetic energy. Here we use the moments of the neutron spectrum to study the relationship between the ion temperature (measured by the variance in the neutron kinetic energy spectrum) and the ion mean kinetic energy (measured by the shift in the mean neutron energy). We observe a departure from the relationship expected for plasmas where the ion relative kinetic energy distribution is Maxwell–Boltzmann, when the plasma begins to burn. Understanding the cause of this departure from hydrodynamic behaviour could be important for achieving robust and reproducible ignition.