压缩氘氚球的热核燃烧特性研究

本文利用LARED-S程序模拟了等密度和等压力条件下压缩氘氚球的热核反应燃烧过程.对于等密度模型,模拟了两个具体算例,与国外计算结果进行了比较,验证了程序的可靠性.对于等压力模型,利用数值模拟给出了热核反应燃烧与压缩氘氚球初始状态之间的关系曲线,分析发现,氘氚装量、压力和主燃料密度的增加有利于提高热核反应放能和燃耗,中心热斑的温度和面密度分别达到70—80 MK和3—4 kg·m^-2时热核反应才有显著的放能,提高主燃料密度,可以适当放宽对中心热斑的点火要求.最后对实际点火靶进行了数值模拟并且与等压力模拟计算结果进行了比较分析. 关键词： 压缩氘氚球 等密度模型 等压力模型 热核反应聚变     

Lasers for ICF with a Controllable Function of Mutual Coherence of Radiation

The current status of laser thermonuclear fusion research in the leading world scientific centers is characterized by the development of superhigh-power multi-channel laser facilities of megajoule pulse-energy level. The development of such laser installations operating in the pulse-repetition mode with a large number of laser beams, which are necessary for high-symmetry irradiation of a spherical thermonuclear target, is an extremely difficult physical and engineering problem. The concept of a special laser with a controllable function of mutual coherence of radiation is proposed. The studies performed demonstrate that a laser based on such a principle has a number of advantages as compared to the conventional schemes of lasers. In particular, the optical scheme of the laser is significantly simplified, and the cost of the output-energy unit is reduced by several times. The influence of radiation coherence on the homogeneity of the thermonuclear target irradiation is analyzed. The feasibility of suppressing the small-scale self-focusing without application of spatial filtration is shown. A module of the laser facility has been triggered to check the validity of the principles proposed for constructing a laser driver for power stations, and the first experimental results are reported. The possibility of controlling the coherence of laser beams used in ICF experiments without violation of the laser--target system matching is demonstrated, as well as controlling the distribution of the laser radiation intensity in the lens focus.     

国际热核聚变堆实验增殖包层模块设计

为了验证国际热核聚变堆(ITER)的产氚和能量获取等性能,各国分别提出了不同的实验增殖模块(TBM)设计方案。其总体功能相同,但具体技术路线有区别,不同之处包括冷却剂选择、产氚材料选择、中子倍增剂选择、产氚区布置形式、面向等离子体材料选择、结构材料选择等方面。通过对各TBM方案进行比较分析,评价了各自的优缺点,提出了未来先进产氚包层方案的设计建议。     

高时间分辨的聚变反应峰值时刻测量

聚变反应峰值时刻是表征惯性约束聚变热核反应的重要参数。在神光Ⅲ原型装置上利用新研制的具有高时间分辨的聚变反应历程测量系统对聚变反应时间过程进行了测量,通过引入时标光获得了对应不同碳氢（CH）烧蚀层厚度的聚变反应峰值时刻数据,测量结果表明:在当前的实验条件下,聚变反应峰值时刻落后入射激光0.7~1.0 ns,增加烧蚀层厚度或氘氚（DT）燃料气压均会导致聚变反应峰值时刻与入射激光间的相对延时增加。     

Conditions for existence of a stationary relativistic compact beam torus

Conditions of creating an absolute magnetic trap for controllable thermonuclear fusion with the help of a high-current relativistic beam of charged particles are considered. It is demonstrated that these conditions are realized for a compact beam torus (CBT) in an intrinsic electromagnetic field. On the other hand, from the virial theorem it follows that for positive beam pressure and positive energy density of the electromagnetic field, no strictly stationary state exists in the empty Minkowski flat space-time. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 75–78, February, 2009.     

Influence of spatial distribution and temporal dynamics of compressed ICF-target parameters on fast ignition efficiency

The fast ignition as, possibly the most efficient method of inertial confinement fusion (ICF) is based on heating a small fusion initiation region (igniter) while the rest of the target is compressed by a compressing driver. We investigate the influence of two factors on the efficiency of fast ignition of ICF-targets. The first factor is the spatial distribution of thermonuclear-fuel parameters formed due to the ICF-target irradiation by the compressing driver. The second one is a mismatch in the time moments of the target maximum compression and the igniter heating by the igniting driver. The main characteristics of fast ignition, namely, the minimum energy of igniter needed to ignite the main ICF-target fuel (ignition energy) and the burn efficiency (ratio between the burnt and initial fuel masses), are investigated in view of numerical simulation. The scale-invariant dependences of the minimum ignition energy E _ig and the burn efficiency are obtained. It is shown that the burn efficiency depends on the spatial heterogeneity of the thermonuclear-fuel parameters much weaker then the ignition energy, but a strong dependence of the burn efficiency on the mismatch in time moments of the maximum compression and ignition is found. In particular, the ignition before the time moment of the maximum compression is more favorable than the ignition at just this moment.     

51(p,n)51Cr reaction from E p 1.9 to 4.5 MeV

The total cross-section for the reaction⁵¹V(p, n)⁵¹Cr has been measured fromE _p 1.9 to 4.5 MeV by using two different techniques: (i) by detecting the neutron using the 4π neutron counter and (ii) by measuring the activity of the residual nucleus⁵¹Cr. The two measurements are consistent with each other and together they are in good agreement with the data of Zyskindet al. The thermonuclear reaction rates have also been extracted starting from these cross-sections.     

One method of producing a high-temperature dense plasma

This paper considers the interaction between an absolutely rigid wall or a steel plate and the rarefaction wave arising in solid deuterium when a 30–150 GPa shock wave arrives at the free surface. It is shown that, in the entropy trace near the wall or interface with the plate, a high-temperature plasma arises, in which a thermonuclear fusion is possible, at least, for shock-wave pressures above 70 GPa. The dimension of the plasma region and the time of its establishment are proportional to the distance between the free surface and the wall. Estimates of the proportionality coefficients are given. It is noted that, in this case, unlike in other methods of high-temperature plasma generation, the time of existence of the plasma may not depend on the sound velocity in it. It is shown that, by using a conical solid-state target wit an exit hole, the shock-wave pressure in solid deuterium can be increased from 10 to 100 GPa. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 3, pp. 15–24, May–June, 2009.     

压缩氘氚球的热核燃烧特性研究

本文利用LARED-S程序模拟了等密度和等压力条件下压缩氘氚球的热核反应燃烧过程.对于等密度模型,模拟了两个具体算例,与国外计算结果进行了比较,验证了程序的可靠性.对于等压力模型,利用数值模拟给出了热核反应燃烧与压缩氘氚球初始状态之间的关系曲线,分析发现,氘氚装量、压力和主燃料密度的增加有利于提高热核反应放能和燃耗,中心热斑的温度和面密度分别达到70—80 MK和3—4 kg·m^-2时热核反应才有显著的放能,提高主燃料密度,可以适当放宽对中心热斑的点火要求.最后对实际点火靶进行了数值模拟并且与等压力模拟计算结果进行了比较分析.     

Determination of the stellar reaction rate for 12C（α,γ）16O： using a new expression with the reaction mechanism

The astrophysical reaction rate of 12C(α, γ)16O plays a key role in massive star evolution. However, this reaction rate and its uncertainties have not been well determined yet, especially at T9=0.2. The existing results even disagree with each other to a certain extent. In this paper, the E1, E2 and total (E1+E2) 12C(α, γ)16O reaction rates are calculated in the temperature range from T9=0.3 to 2 according to all the available cross section data. A new analytic expression of the 12 C(α, γ)16 O reaction rate is brought forward based on the reaction mechanism. In this expression, each part embodies the underlying physics of the reaction. Unlike previous works, some physical parameters are chosen from experimental results directly, instead of all the parameters obtained from fitting. These parameters in the new expression, with their 3σ fit errors, are obtained from fit to our calculated reaction rate from T9=0.3 to 2. Using the fit results, the analytic expression of 12C(α, γ)16O reaction rate is extrapolated down to T9=0.05 based on the underlying physics. The 12C(α, γ)16 O reaction rate at T9=0.2 is (8.78 ± 1.52) × 1015 cm3s-1mol-1. Some comparisons and discussions about our new 12 C(α, γ)16 O reaction rate are presented, and the contributions of the reaction rate correspond to the different part of reaction mechanism are given. The agreements of the reaction rate below T9=2 between our results and previous works indicate that our results are reliable, and they could be included in the astrophysical reaction rate network. Furthermore, we believe our method to investigate the 12C(α, γ)16O reaction rate is reasonable, and this method can also be employed to study the reaction rate of other astrophysical reactions. Finally, a new constraint of the supernovae production factor of some isotopes are illustrated according to our 12C(α, γ)16O reaction rates.