A model for fast electron-driven high-density plasma in the double-cone ignition scheme

A model for fast electron-driven high-density plasma is proposed to describe the effect of injected fast electrons on the temperature and inner pressure of the plasma in the fast heating process of the double-cone ignition(DCI)scheme.Due to the collision of the two low-density plasmas,the density and volume of the high-density plasma vary.Therefore,the ignition temperature and energy requirement of the high-density plasma vary at different moments,and the required energy for hot electrons to heat the plasma also changes.In practical experiments,the energy input of hot electrons needs to be considered.To reduce the energy input of hot electrons,the optimal moment and the shortest time for injecting hot electrons with minimum energy are analyzed.In this paper,it is proposed to inject hot electrons for a short time to heat the high-density plasma to a relatively high temperature.Then,the alpha particles with the high heating rate and PdV work heat the plasma to the ignition temperature,further reducing the energy required to inject hot electrons.The study of the injection time of fast electrons can reduce the energy requirement of fast electrons for the high-density plasma and increase the probability of successful ignition of the high-density plasma.

Evolution of microstructure in reheated coarse-grained zone of G115 novel martensitic heat-resistant steel

Based on the thermal simulation method,a systematical analysis was conducted on the effect of welding peak temperature and the cooling time that takes place from 800 to 500℃ on microstructure,precipitates,substructure and microhardness of the reheated coarse-grained heat-affected zone(CGHAZ)of G115 novel martensitic heat-resistant steel.As revealed from the results,the microstructure of un-altered CGHAZ(UACGHAZ)and supercritically CGHAZ(SCCGHAZ)was lath martensite,and structural heredity occurred.Intercritically reheated CGHAZ(IRCGHAZ)exhibited martensite and over-tempered martensite,and subcritical CGHAZ(SCGHAZ)displayed martensite and under-tempered martensite.The austenite in UACGHAZ and SCCGHAZ was transformed with the diffusion mechanism during the first thermal cycle,but with the non-diffusion mechanism during the second thermal cycle.For this reason,A_(c1) and A_(c3) during the second thermal cycle were significantly lower than those during the first thermal cycle,and A_(c1) and A_(c3) were reduced by nearly 14 and 44℃,respectively.Since the content and stability of the austenite alloy during the second thermal cycle of IRCGHAZ were lower than those during the first thermal cycle,M_(s) increased by nearly 30℃.There were considerable precipitates in the over-tempered region of IRCGHAZ,and the Laves phase was contained,which was not conducive to high-temperature creep property.Moreover,the dislocation density and the number of sub-grains in the region were lower,resulting in a sharp decrease in the microhardness,and it was the weak area in the reheated CGHAZ.