http://www.mdpi.com/journal/energies/special_issues/nuclear_fusion/ Dear Colleagues, Fusion is the energy source of the Sun and Stars. For over 50 years, scientists all over the world have been seeking to develop a process for tapping fusion energy for use on Earth. Fusion takes place most readily between deuterium and tritium, the two heavy isotopes of hydrogen. A gas of these isotopes, called a plasma, must be heated to temperatures of about 100 million degrees Celsius and kept away from material walls of a chamber for a long enough time to release a practical amount of fusion energy in a continuous or semi-continuous stream. There are several approaches to do this. The two flagship facilities are the magnetically confined international tokamak project (ITER) under construction in France and the National Ignition Facility (NIF), a laser-based facility recently came into operation in the U.S. This issue summarizes some of the latest developments in the quest for fusion energy. Dr. Stephen O. Dean Guest Editor Submission All manuscripts should be submitted to energies@mdpi.com with a copy to the Guest Editor. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website. Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed Open Access monthly journal published by MDPI. Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this Open Access journal is 800 CHF per accepted paper. http://www.mdpi.com/1996-1073/3/11/1741/ Providing a historical overview of 50 years of fusion research, a review of the fundamentals and concepts of fusion and research efforts towards the implementation of a steady state tokamak reactor is presented. In 1990, a steady-state tokamak reactor (SSTR) best utilizing the bootstrap current was developed. Since then, significant efforts have been made in major tokamaks, including JT-60U, exploring advanced regimes relevant to the steady state operation of tokamaks. In this paper, the fundamentals of fusion and plasma confinement, and the concepts and research on current drive and MHD stability of advanced tokamaks towards realization of a steady-state tokamak reactor are reviewed, with an emphasis on the contributions of the JAEA. Finally, a view of fusion energy utilization in the 21st century is introduced. http://www.mdpi.com/1996-1073/3/11/1741/ Wed, 10 Nov 2010 00:00:00 CET Energies 2010-11-10 3 11 Review 1741 1789 1996-1073 A Review of Fusion and Tokamak Research Towards Steady-State Operation: A JAEA Contribution 2010-11-10 doi: 10.3390/en3111741 Mitsuru Kikuchi http://www.mdpi.com/1996-1073/3/6/1176/ The feasibility of a new approach of laser fusion in plasma without implosion has been proposed and is discussed using an intense laser. The cross section of the nuclear reaction is increased by enhancing the penetrability of nuclei through the Coulomb barrier. In this approach, an intense laser field of more than 100 PW was required to distort the Coulomb barrier to obtain enough penetrability. An energy gain even with Deuterium-Deuterium (D-D) reaction can be obtained using this scheme in Deuterium plasma. A reactor with neutron and direct conversion of charged particle beam individually is proposed. Charged particles from D-D reaction are guided to the end of the reactor and are directly converted by a MHD scheme into electric energy. The energy recovery rate is high and requires a small amount of laser energy, which may make the energy cost cheaper than that of a fission reactor. http://www.mdpi.com/1996-1073/3/6/1176/ Tue, 08 Jun 2010 00:00:00 CEST Energies 2010-06-08 3 6 Review 1176 1193 1996-1073 New Laser Fusion and Its Gain by Intense Laser 2010-06-08 doi: 10.3390/en3061176 Imasaki Li http://www.mdpi.com/1996-1073/3/6/1067/ Fifty years ago, the secrecy surrounding magnetically controlled thermonuclear fusion had been lifted allowing researchers to freely share technical results and discuss the challenges of harnessing fusion power. There were only four magnetic confinement fusion concepts pursued internationally: tokamak, stellarator, pinch, and mirror. Since the early 1970s, numerous fusion designs have been developed for the four original and three new approaches: spherical torus, field-reversed configuration, and spheromak. At present, the tokamak is regarded worldwide as the most viable candidate to demonstrate fusion energy generation. Numerous power plant studies (>50), extensive R&D programs, more than 100 operating experiments, and an impressive international collaboration led to the current wealth of fusion information and understanding. As a result, fusion promises to be a major part of the energy mix in the 21st century. The fusion roadmaps developed to date take different approaches, depending on the anticipated power plant concept and the degree of extrapolation beyond ITER. Several Demos with differing approaches will be built in the US, EU, Japan, China, Russia, Korea, India, and other countries to cover the wide range of near-term and advanced fusion systems. http://www.mdpi.com/1996-1073/3/6/1067/ Tue, 01 Jun 2010 00:00:00 CEST Energies 2010-06-01 3 6 Review 1067 1086 1996-1073 Fifty Years of Magnetic Fusion Research (1958–2008): Brief Historical Overview and Discussion of Future Trends 2010-06-01 doi: 10.3390/en30601067 El-Guebaly http://www.mdpi.com/1996-1073/3/5/1014/ Recent advances in space-based heliospheric observations, laboratory experimentation, and plasma simulation codes are creating an exciting new cross-disciplinary opportunity for understanding fast energy release and transport mechanisms in heliophysics and laboratory plasma dynamics, which had not been previously accessible. This article provides an overview of some new observational, experimental, and computational assets, and discusses current and near-term activities towards exploitation of synergies involving those assets. This overview does not claim to be comprehensive, but instead covers mainly activities closely associated with the authors’ interests and reearch. Heliospheric observations reviewed include the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) on the National Aeronautics and Space Administration (NASA) Solar Terrestrial Relations Observatory (STEREO) mission, the first instrument to provide remote sensing imagery observations with spatial continuity extending from the Sun to the Earth, and the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Japanese Hinode spacecraft that is measuring spectroscopically physical parameters of the solar atmosphere towards obtaining plasma temperatures, densities, and mass motions. The Solar Dynamics Observatory (SDO) and the upcoming Solar Orbiter with the Heliospheric Imager (SoloHI) on-board will also be discussed. Laboratory plasma experiments surveyed include the line-tied magnetic reconnection experiments at University of Wisconsin (relevant to coronal heating magnetic flux tube observations and simulations), and a dynamo facility under construction there; the Space Plasma Simulation Chamber at the Naval Research Laboratory that currently produces plasmas scalable to ionospheric and magnetospheric conditions and in the future also will be suited to study the physics of the solar corona; the Versatile Toroidal Facility at the Massachusetts Institute of Technology that provides direct experimental observation of reconnection dynamics; and the Swarthmore Spheromak Experiment, which provides well-diagnosed data on three-dimensional (3D) null-point magnetic reconnection that is also applicable to solar active regions embedded in pre-existing coronal fields. New computer capabilities highlighted include: HYPERION, a fully compressible 3D magnetohydrodynamics (MHD) code with radiation transport and thermal conduction; ORBIT-RF, a 4D Monte-Carlo code for the study of wave interactions with fast ions embedded in background MHD plasmas; the 3D implicit multi-fluid MHD spectral element code, HiFi; and, the 3D Hall MHD code VooDoo. Research synergies for these new tools are primarily in the areas of magnetic reconnection, plasma charged particle acceleration, plasma wave propagation and turbulence in a diverging magnetic field, plasma atomic processes, and magnetic dynamo behavior. http://www.mdpi.com/1996-1073/3/5/1014/ Tue, 25 May 2010 00:00:00 CEST Energies 2010-05-25 3 5 Review 1014 1048 1996-1073 Exploiting Laboratory and Heliophysics Plasma Synergies 2010-05-25 doi: 10.3390/en30501014 Dahlburg Amatucci Brown Chan Chen Cothran Chua Dahlburg Doschek Egedal Forest Howard Huba Ko Krall Laming Lin Linton Lukin Murphy Rakowski Socker Tylka Vourlidas Warren Wood http://www.mdpi.com/1996-1073/3/5/973/ We found three errors in our paper published in Energies [1]. The corrections are as following: [...] http://www.mdpi.com/1996-1073/3/5/973/ Tue, 11 May 2010 00:00:00 CEST Energies 2010-05-11 3 5 Correction 973 973 1996-1073 Correction: Energy Resources in the Future 2010-05-11 doi: 10.3390/en3050973 Tomabechi http://www.mdpi.com/1996-1073/3/4/711/ Recent extensive and systematic numerical experiments have uncovered new insights into plasma focus fusion devices including the following: (1) a plasma current limitation effect, as device static inductance is reduced towards very small values; (2) scaling laws of neutron yield and soft x-ray yield as functions of storage energies and currents; (3) a global scaling law for neutron yield as a function of storage energy combining experimental and numerical data showing that scaling deterioration has probably been interpreted as neutron ‘saturation’; and (4) a fundamental cause of neutron ‘saturation’. The ground-breaking insights thus gained may completely change the directions of plasma focus fusion research. http://www.mdpi.com/1996-1073/3/4/711/ Mon, 12 Apr 2010 00:00:00 CEST Energies 2010-04-12 3 4 Review 711 737 1996-1073 Numerical Experiments Providing New Insights into Plasma Focus Fusion Devices 2010-04-12 doi: 10.3390/en3040711 Lee Saw http://www.mdpi.com/1996-1073/3/4/686/ Recent statistics indicate that in 2005 the world consumed about 0.5 ZJ (ZJ = 1021 Joules) of energy. If one assumes that the future world population stabilizes at 10 billions, and the people consume a similar amount of energy per capita to that of the people in the presently developed countries, the world will need about 2 ZJ a year. A recent survey of the available future energy resources indicates that the energies recoverable from coal, oil and gas are only 23 ZJ, 6.7 ZJ and 6.4 ZJ, respectively. Other energy resources such as solar and wind have problems of fluctuation due to the weather conditions. However, the energy expected from known Uranium resources by breeder reactors is 227 ZJ and that from Lithium by fusion reactors is more than 175 ZJ. Therefore, it is important to make efforts to develop and use breeder reactors and fusion reactors to supply a major part of the energy need in the future. http://www.mdpi.com/1996-1073/3/4/686/ Thu, 08 Apr 2010 00:00:00 CEST Energies 2010-04-08 3 4 Review 686 695 1996-1073 Energy Resources in the Future 2010-04-08 doi: 10.3390/en3040686 Tomabechi http://www.mdpi.com/1996-1073/3/3/277/ The NSTAB nonlinear stability code solves differential equations in conservation form, and the TRAN Monte Carlo test particle code tracks guiding center orbits in a fixed background, to provide simulations of equilibrium, stability, and transport in tokamaks and stellarators. These codes are well correlated with experimental observations and have been validated by convergence studies. Bifurcated 3D solutions of the 2D tokamak problem have been calculated that model persistent disruptions, neoclassical tearing modes (NTMs) and edge localized modes (ELMs) occurring in the International Thermonuclear Experimental Reactor (ITER), which does not pass the NSTAB simulation test for nonlinear stability. So we have designed a quasiaxially symmetric (QAS) stellarator with similar proportions as a candidate for the demonstration (DEMO) fusion reactor that does pass the test [1]. The configuration has two field periods and an exceptionally accurate 2D symmetry that furnishes excellent thermal confinement and good control of the prompt loss of alpha particles. Robust coils are found from a filtered form of the Biot-Savart law based on a distribution of current over a control surface for the coils and the current in the plasma defined by the equilibrium calculation. Computational science has addressed the issues of equilibrium, stability, and transport, so it remains to develop an effective plan to construct the coils and build a diverter. http://www.mdpi.com/1996-1073/3/3/277/ Fri, 26 Feb 2010 00:00:00 CET Energies 2010-02-26 3 3 Article 277 284 1996-1073 The DEMO Quasisymmetric Stellarator 2010-02-26 doi: 10.3390/en3030277 Paul R. Garabedian Geoffrey B. McFadden