Plasma Science in the University

An historical perspective is provided on the role of fusion research support in the training of students in the field of plasma physics.     

Plasma Science in the University of California System

A survey is presented of the plasma science research underway in the University of California (UC) system. Plasma research is carried out in at least fifteen different departments at seven of the nine UC campuses, as well as at the three UC-managed DOE laboratories (Lawrence Berkeley National Laboratory (LBNL), Lawrence Livermore National Laboratory (LLNL), and Los Alamos National Laboratory (LANL)). In addition, many of these activities involved strong collaborations among UC sites as well as with institutions outside of the UC system. The environment for plasma science at UC ranges from small-scale research activities to large programs. Students have the opportunity of being trained in a team setting or in working individually with a professor. Research activities are supported by both government and private sector funding and have a wide range of applications and motivations. These applications can be grouped into general categories such as commercial manufacturing, energy, defense, development of new tools, and fundamental understanding of our universe.     

Plasma Science and Its Applications

An overview is provided of the papers presented at Fusion Power Associates annual meeting and symposium on the topic Plasma Science and Its Applications, held June 3–5, 1998 in Washington, DC. Only those papers not otherwise contained in the current issue of the JFE are covered.     

Relevance of Plasma Science to Particle Accelerators

In following the theme of this Symposium, Plasma Science and Its Applications, we may be suggesting to some readers that the other applications of Plasma Science somehow justify the existence of a field traditionally devoted to fusion energy. In fact, we do not believe that plasma science can or should be justified for its spin-off contributions. Nevertheless, the unity of science would be seriously threatened by a precipitous decline in the support for plasma science. It is that unity which repeatedly has been verified as one looks for how advances in one field are crucial to several other seemingly fundamentally different fields. Thus it is in this case, as a representative of the community of Particle Accelerator Scientists, that we show four significant areas in which the methods and the results of plasma science have been applied to Accelerator Science. We have deliberately skipped plasma ion sources which are perhaps the most obvious application of plasmas to accelerators. Two of our four examples are cases in which the computational methods of plasma science have been adopted, and two are examples in which the plasmas themselves are employed. One of each category are now actively in use and the other one in each category is being used to develop or design new devices.     

The Plasma Science and Innovation Center Interfacing Group

The Interfacing Group of the Plasma Science and Innovation Center (PSI-Center), – http://www.psicenter.org facilitates simulations of collaborating Emerging Concept (EC) experiments. This includes helping set up new simulations for experiments, assisting in comparison of simulations with experimental data, acquiring and disseminating information about simulations to PSI-Center computational groups, and acting as a conduit of information between experiments. The Interfacing Group also administers a local development computational cluster and network.     

Technical Summary of the First U.S. Plasma Jet Workshop

This paper provides a technical summary of the first U.S. Plasma Jet Workshop, which was sponsored by the DOE Office of Fusion Energy Sciences and held at Los Alamos National Laboratory on January 24–25, 2008. The purpose of the workshop was to bring together members of the national plasma jet research community in order to discuss ongoing research and identify research needs and opportunities in plasma jets and their applications, which include fundamental studies of high energy density (HED) plasmas, magneto-inertial fusion (MIF), laboratory astrophysics, and disruption mitigation and fueling for magnetic confinement devices. Over the course of the workshop, about equal time was devoted to short technical talks and group discussions.     

Education Outreach

A survey is presented on the Education Outreach activities that are sponsored by the Department of Energy's Office of Fusion Energy Sciences, with emphasis on the scope of these activities and the history behind the effort.     

Nonneutral Plasma Science Issues for Heavy Ion Drivers

A review of nonneutral plasma science issues for heavy ion drivers is presented. The requirements on transverse and longitudinal focusing at the target lead to constraints on the 6D phase space. Mechanisms which act to prevent focusability, including emittance growth, space charge and instabilities are discussed. Experiments which have explored and validated our understanding of beam transport and focusability of space-charge dominated heavy ion beams are described.     

Near Term Applications of Plasma Science and Fusion Research: National Laboratory Perspectives

This paper describes some of the near-term practical applications of plasma science from the perspective of National Laboratories involved with fusion research for many years. The first half of the paper presents suggestions for maintaining a healthy national program in this area. The second part of the paper gives specific examples of near-term plasma applications research at our laboratories.     

The Formation of a Tokamak-like Plasma in Initial Experiments Using an Outboard Plasma Gun Current Source

Solenoid-free tokamak startup via point-source DC helicity injection is demonstrated on the Pegasus Toroidal Experiment using a high current density, low impurity plasma gun mounted near the outboard midplane. A threshold in the vacuum vertical magnetic field strength that allows the injected current filament to relax into a tokamak-like topology is observed. A simple 2-D model of the vacuum magnetic field suggests this threshold is the maximum field strength that allows a toroidally connected field null to form. Discharges with I _p ≈ 17 kA are produced using less than 2 kA of injected current and no inductive drive. The tokamak-like discharges exhibit current decay times about five times longer than the injected current decay, expansion of the plasma into the vacuum region and a significant increase in the line-integrated density.     

用于激光等离子体诊断的探针光工程化改造

探针光系统作为激光等离子体诊断的探针光源,它通过倍频和受激喇曼散射,将波长为1054nm、脉宽约为1ns激光转换成波长为308nm、脉宽小于60ps、能量大于1mJ的紫外光。通过预研研究和工程化改造,结果表明:探针光系统输出能量大于1mJ、脉宽小于30ps、均匀性较好、运行成功率大于90%,达到了研制标的,可满足激光等离子体诊断的要求。     

等离子体表面处理的正电子湮没研究

本文将正电子湮没技术用于等离子体喷涂的研究。测量了等离子体喷涂合金的缺陷以及缺陷的退火效应，观察到了正电子寿命的一些异常现象。     

Experimental Study of Plasma Materials' Interaction in Plasma Focus “Dena”

It is widely recognized that plasma material interaction in fusion devices is a critical issue that affects the overall machine performance. The process of material selection with a low degradation effect on the confined plasma and on the nuclear fusion production in tokamaks is of great importance. However, plasma materials' interaction studies in tokamaks have some limitations, so it is suggested that a new method for investigating this phenomenon be developed. The high capabilities of plasma focus devices allow one to simulate the interaction studies of tokamak plasma and first-wall materials. Our experiments were performed on a 90-kJ Filippov-type plasma focus, Dena. Experimental results clearly show the influence of materials on the neutron yield and neutron production mechanisms.     

Enabling Technology in Support of Fusion Science

This paper summarizes remarks made at Fusion Power Associates annual meeting, July 17, 2000 in San Diego. It describes the U.S. Department of Energy Office of Fusion Enegy Sciences programs in plasma and fusion technology in support of the U. S. fusion energy sciences program.     

新型多元掺杂面对等离子体碳基材料的性能研究

对方案和机理的研究 ,在国内相关单位采取优势互补的方法进行合作 ,基于理论和实验 ,得出了高强度、高热导、低溅射掺杂石墨和碳 碳 (C C)复合材料的最佳配方 ;合适的工艺路线和工艺参数 ;掺杂石墨热导率提高 4倍以上 ;化学溅射产额下降 1个数量级 ;抗辐照增强升华和热解吸均有明显改善 ;抗等离子体辐照综合性能亦有较大提高 ,经受 1 0 0多次的等离子体放电轰击无裂纹     

Low-Energy Plasma Focus as a Tailored X-Ray Source

A low-energy (2.3 kJ) plasma focus energized by a single 32-F capacitor charged at 12 kV with filling gases hydrogen, neon, and argon is investigated as an X-ray source. Experiments are conducted with a copper and an aluminum anode. Specifically, attention is given to tailoring the radiation in different windows, e.g., 1.2–1.3 keV, 1.3–1.5 keV, 2.5–5 keV, and Cu-K line radiation. The highest X-ray emission is observed with neon filling and the copper anode in the 1.2–1.3 keV window, which we speculate to be generated due to recombination of hydrogenlike neon ions with a few eV to a few 10s of eV electrons. The wall-plug efficiency of the device is found to be 4%. The other significant emission occurs with hydrogen filling, which exhibits wall-plug efficiency of 1.7% for overall X-ray emission and 0.35% for Cu-K line radiation. The emission is dominated by the interaction of electrons in the current sheath with the anode tip. The emission with the aluminum anode and hydrogen filling is up to 10 J, which corresponds to wall-plug efficiency of 0.4%. The X-ray emission with argon filling is less significant.     

Plasma properties of laser-ablated St target in air

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Dense Plasma Injection Experiment at MCX

We present preliminary results of the High Density Plasma Injection Experiment at the Maryland Centrifugal Experiment (MCX). HyperV Technologies Corp. has designed, built, and installed a prototype coaxial gun to drive rotation in MCX. This gun has been designed to avoid the blow-by instability via a combination of electrode shaping and a tailored plasma armature. An array of diagnostics indicates the gun is capable of plasma jets with a mass of 160 μg at 70 km/s with an average plasma density above 10¹⁵ cm⁻³. Preliminary measurements are underway at MCX to understand the penetration of the plasma jet through the MCX magnetic field and the momentum transfer from the jet to the MCX plasma. Data will be presented for a wide range of MCX field parameters, and the prospects for future injection experiments will be evaluated.     

C<Subscript>60</Subscript>-Fullerene Hyper-Velocity High-Density Plasma Jets for MIF and Disruption Mitigation

We present an innovative idea to use hyper-velocity (>30 km/s) high-density (>10¹⁷ cm⁻³) plasma jets of D-T/H and C₆₀-fullerene for magneto-inertial fusion (MIF), high energy density laboratory plasma (HEDLP), and disruption mitigation in magnetic fusion plasma devices. The mass (~1–2 g) of sublimated C₆₀ and hydrogen (or D-T fuel) produced in a pulsed power source is ionized and accelerated as a plasma slug in a coaxial plasma accelerator. For MIF/HEDLP we propose to create a magnetized plasma target by injecting two high-Mach number high-density jets with fuel (D-T) and liner (C₆₀/C) structure along the axis of a pulsed magnetic mirror. The magnetized target fusion (MTF) plasma created by head-on collision and stagnation of jets is compressed radially by a metallic liner (Z-pinch) and axially by the C₆₀/C liner. For disruption mitigation, the C₆₀ plasma jets were shown to be able to provide the required impurity mass (J Fusion Energy 27:6, 2008).     

特种废物等离子体处理技术的应用与研究

简单介绍了等离子体的基本概念及其热等离子体废物处理技术的基本原理,从几个方面总结介绍了固体废物等离子体处理技术的应用与研究。与常规处理方法相比较,采用热等离子体特种废物处理技术其先进性和优越性得到进一步显现,成为特种废物处理领域最有发展前途,最引人关注的高科技处理技术之一。文章还简单介绍了作者在实验室热等离子体技术工作中的一些实验结果以及核工业西南物理研究院在引进、吸收、消化、发展国外等离子体炬和在研制等离子体炬新型电源方面所做的一些工作。