Non-equilibrium between ions and electrons inside hot spots from National Ignition Facility experiments

• Published in: Matter and radiation at extremes Vol. 2; no. 1; pp. 3 - 8
• Main Authors: Fan, Zhengfeng, Liu, Yuanyuan, Liu, Bin, Yu, Chengxin, Lan, Ke, Liu, Jie
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2017; AIP Publishing LLC
• Subjects: High-foot experiments; Hot-spot ignition conditions relaxation; Ion-electron non-equilibrium; Ion-electron non-equilibrium; 52.57.-z; High-foot experiments; 52.30.-q; Hot-spot ignition conditions relaxation
• ISSN: 2468-080X; 2468-2047; 2468-080X
• DOI: 10.1016/j.mre.2016.11.003

The non-equilibrium between ions and electrons in the hot spot can relax the ignition conditions in inertial confinement fusion [Fan et al., Phys. Plasmas 23, 010703 (2016)], and obvious ion-electron non-equilibrium could be observed by our simulations of high-foot implosions when the ion-electron relaxation is enlarged by a factor of 2. On the other hand, in many shots of high-foot implosions on the National Ignition Facility, the observed X-ray enhancement factors due to ablator mixing into the hot spot are less than unity assuming electrons and ions have the same temperature [Meezan et al., Phys. Plasmas 22, 062703 (2015)], which is not self-consistent because it can lead to negative ablator mixing into the hot spot. Actually, this non-consistency implies ion-electron non-equilibrium within the hot spot. From our study, we can infer that ion-electron non-equilibrium exists in high-foot implosions and the ion temperature could be ∼9% larger than the equilibrium temperature in some NIF shots.