惯性约束聚变低温冷冻氘氚靶制备技术

低温冷冻氘氚靶对于惯性约束聚变研究至关重要,主要有塑料微球靶、金属铍球靶、泡沫球壳靶等。根据微球球壳材质的不同,采用不同的低温冷冻氘氚靶制备技术。塑料微球靶采用“高压充氘氚-冷冻法”或“充气管充气法”;金属铍球靶采用“低温、低压冷凝法”或“高温、高压扩散连接半球壳法”;多孔泡沫球壳靶采用“球壳材料吸附氘氚液体法”。本文简述上述技术和方法的发展状况和趋势。     

Studies on the Dynamics of D–T Fusion Reaction Based on the Relativistic Equilibrium Velocity Distribution

The Coulomb barrier is in general much higher than thermal energy. Nuclear fusion reactions occur only among few protons and nuclei (i.e., deuterium and tritium) with higher relative energies than Coulomb barrier. It is the equilibrium velocity distribution of these high-energy protons and nuclei that participates in determining the rate of nuclear fusion reactions. In the circumstance it is inappropriate to use the Maxwellian velocity distribution for calculating the nuclear fusion reaction rate. We use the relativistic equilibrium has a reduction factor with respect to that based on the Maxwellian distribution, which factor depends on the temperature, reduced mass and atomic numbers of the studied nuclear fusion reactions. In this paper, we concluded at energy range 10⁵ (keV) ≤ E ≤ 10⁶ (keV), that is smaller than reduced mass energy of deuterium–tritium, m _r c ², the numerical values of R and R _M are not different from each other very much, but by increasing energy near the region of m _r c ² the difference between them are visible, also by increasing energy for example 9 × 10⁶ (keV) ≤ E ≤ 10 × 10⁶ (keV) the difference is obviously more visible. Therefore, we have to use relativistic equilibrium velocity distribution instead of Maxwellian velocity distribution.     

The Rationale for an Expanded Inertial Fusion Energy Program

The rationale for an expanded effort on the development of inertial fusion as an energy source is discussed. It is argued that there should be a two-pronged, complementary approach to fusion energy development over the next two to three decades: (1) Magnetic Fusion (MFE) via ITER and the supporting magnetic domestic program and (2) Inertial Fusion (IFE), a credible, affordable approach that exploits unique US strengths and current world leadership. IFE is only a few years away from demonstration of single-shot ignition and fusion energy gain via NIF. Enhanced funding for IFE R&D is needed in the near-term in order to prepare to expeditiously proceed beyond NIF to the energy application of inertial fusion.     

StarDriver: A Flexible Laser Driver for Inertial Confinement Fusion and High Energy Density Physics

We propose a novel method to minimize laser–plasma instabilities and improve laser–plasma coupling by the use of multi-beam laser architecture with a large system frequency bandwidth and many beamlets per unit solid angle. The StarDriver?, laser driver is constructed from 10⁴ to 10⁵ individual lasers, each delivering nominally 100 J in pulses of ~3–30 ns at a nominal wavelength of ~355 nm with better than 3–5 diffraction-limited performance. The beamlets are individually relatively narrowband to facilitate maximum laser performance, but the ensemble of beamlets span a wide frequency range. Currently available laser media enable Δω/ω ~ 2 % at 355 nm with the possibility of system bandwidths approaching 10 % in the future. The many beamlets of StarDriver? provide optimal asymptotic smoothing for hydrodynamic instabilities (0–1 %), innovative focusing strategies including zooming, and the large bandwidth enables extremely rapid hydrodynamic smoothing times ~30 fs. The distribution of frequencies among the beamlets allows flexibility for fine control of the seeding of the Rayleigh–Taylor instability. The ultra-broad bandwidth combined with the large total k-spectrum of the laser drive in the plasma corona may enable complete suppression of the most problematic laser–plasma instabilities such as stimulated Brillouin backscatter, stimulated Raman scatter, cross-beam energy transfer, and the two plasmon decay instability. StarDriver? offers potentially superior flexibility in laser drivers for inertial confinement fusion, enabling almost arbitrary sequencing of wavelength, polarization, focus, and fine control of the spatio-temporal properties of the drive in the corona. The highly modular strategy of StarDriver? should enable an attractive development pathway as well as maximizing overall system efficiency.     

气凝胶的制备及其在惯性约束聚变实验中的应用

气凝胶是惯性约束聚变(ICF)实验中的一种理想的靶材料.文章介绍SiO2气凝胶、有机和碳气凝胶、二元气凝胶、掺杂SiO2气凝胶和其它几种气凝胶的研制,探讨了气凝胶在ICF相关研究领域的应用.     

Condensed Atomic Hydrogen as a Possible Target in Inertial Confinement Fusion (ICF)

H atom Rydberg matter (RM) in excitation state n = 1 is concluded to be a form of metallic hydrogen [Badiei S, Holmlid L (2004) J Phys Condens Matter 16:7017]. This material can be produced at low pressure. This condensed form of hydrogen may be very useful as a dense hydrogen inertial confinement fusion (ICF) target, being almost metallic and ten times denser than solid (frozen) diatomic hydrogen used at present. Coulomb explosions and plasma formation are initiated in condensed atomic hydrogen even by relatively weak nanosecond pulsed lasers. The protons emitted with high directivity in these explosions are energetic, corresponding to T = 10⁵ K, and they may be utilized to give strong compression of the material. The fastest protons observed at up to 1 keV indicate a compression considerably higher than that required for “fast ignition” fusion.     

Report of the FEAC Inertial Fusion Energy Review Panel: July 1996

This report presents the results and recommendations of the U. S. Department of Energy Fusion Energy Advisory Committee (FEAC) review of its Inertial Fusion Energy (IFE) program. The subpanel charged with the review was chaired by John Sheffield of Oak Ridge National Laboratory. The FEAC, to which the subpanel reported, was chaired by Robert Conn of the University of California at San Diego.     

A Review of the U.S. Department of Energy's Inertial Fusion Energy Program

This is the final report of a panel set up by the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee (FESAC) in response to a charge letter from Dr. Ray Orbach (Appendix A). In that letter, Dr. Orbach asked FESAC for an assessment of the present status of inertial fusion energy (IFE) research carried out in contributing programs. These programs include the heavy ion (HI) beam, the high average power laser (HAPL), and Z-Pinch drivers and associated technologies, including fast ignition (FI). This report, presented to FESAC on March 29, 2004, and subsequently approved by them (Appendix B), presents FESAC's response to that charge.     

可加工SiO2气凝胶及其惯性约束聚变靶微柱制备

以正硅酸乙酯（TEOS）为前驱体，采用酸碱两步催化法制备SiO₂醇凝胶。醇凝胶分别经TEOS母液、六甲基二硅胺烷（HMDSA）处理后，采用CO₂超临界干燥法制备出密度在30～100mg/cm³的SiO₂气凝胶。用傅立叶变换红外光谱（FTIR）对疏水性SiO₂气凝胶进行了表征，并用扫描电镜图研究了气凝胶改性前后的微观网络结构。改性后的气凝胶微观骨架变大，部分细小的网络结构消失。改性后的气凝胶在潮湿环境中具有极好的尺寸稳定性和疏水性能。用精密车床加工出了满足惯性约束聚变物理试验要求的ICF靶微柱。     

Energy Confinement Scaling Predictions for the Stabilized Tandem Mirror

The absence of toroidal curvature and the relatively weak internal parallel currents in a tandem mirror gives the system favorable stability and transport properties. GAMMA-10 experiments demonstrate that sheared plasma rotation suppresses turbulent radial losses through control of the radial potential profiles. Recent achievements of the GAMMA-10 include 3 keV ion confinement potentials and T _e ≥ 800 eV. Total energy confinement times for the GAMMA-10 experiment exceed by an order of magnitude the corresponding empirical confinement times in toroidal devices. At the temperatures achieved in the GAMMA-10, the end loss rate τ_p ≃ 100 ms so that radial losses determine τ_E, as intended in tandem mirror reactor designs. Drift-wave results on radial confinement times developed using Bohm, gyro-Bohm, and electron temperature gradient (ETG) scalings imply that the tandem mirror has a qualitatively different form of drift-wave radial transport from that in toroidal devices. Drift-wave eigenmodes for the GAMMA-10 are analyzed for the fluctuating electrostatic potential and magnetic perturbations.     

ICF靶中的纳米金属功能材料研究进展

本文介绍了中国工程物理研究院激光聚变研究中心在激光惯性约束聚变（ICF）和强辐射源材料研究中涉及到的一些纳米金属功能材料的最新研究进展。主要包括自悬浮定向流金属纳米粉末材料制备与性能研究,介质阻挡放电金属纳米粉末表面包覆研究,真空热压成型的纳米晶体材料研究,以及低密度高孔隙率的泡沫镍金属材料、纳米多孔Cu材料和Au泡沫材料研究;在团簇材料、纳米成型材料研究方面,涉及到了过渡金属、贵金属小团簇材料的几何构型和静电极化率特性的理论模拟研究,以及三角形、六边形、棒状、立方体等特殊纳米结构和形状的Ag、Au金属纳米激光X光转换材料研究。     

A Plan for the Development of Fusion Energy

This is the final report of a panel set up by the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee (FESAC) in response to a charge letter dated September 10, 2002 from Dr. Ray Orbach, Director of the DOE's Office of Science. In that letter, Dr. Orbach asked FESAC to develop a plan with the end goal of the start of operation of a demonstration power plant in approximately 35 years. This report, submitted March 5, 2003, presents such a plan, leading to commercial application of fusion energy by mid-century. The plan is derived from the necessary features of a demonstration fusion power plant and from the time scale defined by President Bush. It identifies critical milestones, key decision points, needed major facilities and required budgets. The report also responds to a request from DOE to FESAC to describe what new or upgraded fusion facilities will best serve our purposes over a time frame of the next twenty years.     

Effect of Lithium Enrichment on the Tritium Breeding Characteristics of Various Breeders in a Fusion Driven Hybrid Reactor

Selection of lithium containing materials is very important in the design of a deuterium–tritium (DT) fusion driven hybrid reactor in order to supply its tritium self-sufficiency. Tritium, an artificial isotope of hydrogen, can be produced in the blanket by using the neutron capture reactions of lithium in the coolants and/or blanket materials which consist of lithium. This study presents the effect of lithium-6 enrichment in the coolant of the reactor on the tritium breeding of the hybrid blanket. Various liquid–solid breeder couples were investigated to determine the effective breeders. Numerical results pointed out that the tritium production increased with increasing lithium-6 enrichment for all cases.     

Study of Fuel Ratios on the Fusion Reactivity in an Inertial Electrostatic Confinement Device Using a Residual Gas Analyzer

Gridded Inertial Electrostatic confinement (IEC) devices are of interest due to their flexibility in burning advanced fuels, their tuning ability of the applied voltage to the reaction cross-section. Although this device is not suitable for power production in its present form, it does have several near term applications. The number of applications of this device increases with increasing fusion reactivity. These devices are simple to operate but are inherently complicated to understand and an effort to incrementally understand the device to improve its operational efficiency is underway at University of Wisconsin, Madison. Of all the parameters under study we are focusing on the effects of flow rate and flow ratio on the fusion reactivity in the present paper. Experiments were conducted to understand the influence of fuel flow ratio on the fusion reactions. The residual gas analyzer (RGA) was used to study the impurity concentration as the flow ratio was changed. It was observed that the higher flow rate resulted in reduced impurity levels and hence an increase in fusion rate. Several different species of gases were detected, some of these molecules formed inside the RGA analyzer. The flow ratio scan revealed that the optimum mixture of D₂ with ³He to be D₂:³He::1:2 for maximum D–³He fusion rate.     

Non-Uniformity of Heavy-Ion Beam Irradiation on a Direct-Driven Pellet in Inertial Confinement Fusion

Heavy-ion-driven fusion (HIF) is a scheme to achieve inertial confinement fusion (ICF). Investigation of the non-uniformity of heavy-ion beam (HIB) irradiation is one of the key issues for ICF driven by powerful heavy-ion beams. Ions in HIB impinge on the pellet surface and deposit their energy in a relatively deep and wide area. Therefore, the non-uniformity of HIB irradiation should be evaluated in the volume of the deposition area in the absorber layer. By using the OK1 code with some corrections, the non-uniformityof heavy-ion beam irradiation for the different ion beams on two kinds of targets were evaluated in 12-, 20-, 60- and 120-beam irradiation schemes. The root-mean-square (RMS) non-uniformity value becomes σRMS= 8. 39% in an aluminum mono-layer pellet structure and σRMS= 6.53% in a lead-aluminum layer target for the 12-uranium-beam system. The RMS non-uniformity for the lead-aluminum layer target was lower than that for the mono-layer target. The RMS and peak-to-valley (PTV) non-uniformities are reduced with the increase in beam number, and low at the Bragg peak layer.     

Overview of Safety and Environmental Issues for Inertial Fusion Energy

This paper summarizes safety and environmental issues of Inertial Fusion Energy (IFE): inventories, effluents, maintenance, accident safety, waste management, and recycling. The fusion confinement approach among inertial and magnetic options affects how the fusion reaction is maintained and which materials surround the reaction chamber. The target fill technology has a major impact on the target factory tritium inventory. IFE fusion reaction chambers usually employ some means to protect the first structural wall from fusion pulses. This protective fluid or granular bed also moderates and absorbs most neutrons before they reach the first structural wall. Although the protective fluid activates, most candidate fluids have low activation hazard. Hands-on maintenance seems practical for the driver, target factory, and secondary coolant systems; remote maintenance is likely required for the reaction chamber, primary coolant, and vacuum exhaust cleanup systems. The driver and fuel target facility are well separated from the main reaction chamber.     

Report of the Integrated Program Planning Activity for the U.S. Department of Energy Fusion Energy Sciences Program

This report of the Integrated Program Planning Activity (IPPA) has been prepared in response to a recommendation by the Secretary of Energy Advisory Board that, Given the complex nature of the fusion effort, an integrated program planning process is an absolute necessity. We therefore undertook this activity to integrate the various elements of the program, to improve communication and performance accountability across the program, and to show the interconnectedness and interdependency of the diverse parts of the national Fusion Energy Sciences Program. This report is based on the September 1999 Fusion Energy Sciences Advisory Committee's (FESAC) report Priorities and Balance within the Fusion Energy Sciences Program. In its December 5, 2000, letter to the Director of the Office of Science, the FESAC reaffirmed the validity of the September 1999 report and stated that the IPPA presents a framework and process to guide the achievement of the 5-year goals listed in the 1999 report. The report also outlines a process for establishing a database for the fusion research program that will indicate how each research element fits into the overall program. This database will also include near-term milestones associated with each research element and will facilitate assessments of the balance within the program at different levels.     

Realizing the Promise of Fusion Energy: Final Report of the Task Force on Fusion Energy, August 1999

In December 1998, Secretary of Energy Bill Richardson asked the Secretary of Energy Advisory Board to form a Task Force on Fusion Energy to conduct a review of the Department's fusion energy technologies, both inertial and magnetic, and to provide recommendations as to the role of these technologies as part of a national fusion energy research program. This report reflects the Task Force's response to the request.     

Report of the Second Fusion Energy Sciences Committee of Visitors

This report summarizes the findings and recommendations of the second Committee of Visitors (COV) whose charge was to review the manner in which the U. S. Department of Energy’s Office of Fusion Energy Science (OFES) manages certain programs under its charter. The specific programs reviewed by this COV involve confinement innovation and basic plasma sciences. The charge letter from the Department of Energy is included as Appendix A.     

Report of the First Fusion Energy Sciences Committee of Visitors

This is the final report of a Committee of Visitors (COV) set up by the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee (FESAC) in response to a charge letter from DOE Office of Science Director Raymond Orbach (Appendix A). In that letter, Dr. Orbach asked FESAC to assess matters pertaining to program decisions for the DOE's fusion theory and computation programs. This report, submitted to FESAC on March 29, 2004, and subsequently approved by them (Appendix B), presents FESACs response to that charge.