DOCSLIB.ORG

Recent Results of Deuterium Experiment on the Large Helical Device and Its Contribution to the Fusion Reactor Development

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Recent Results of Deuterium Experiment on the Large Helical Device and Its Contribution to the Fusion Reactor Development RECENT RESULTS OF DEUTERIUM EXPERIMENT ON THE LARGE HELICAL DEVICE AND ITS CONTRIBUTION TO THE FUSION REACTOR DEVELOPMENT Masaki Osakabe National Institute for Fusion Science IAEA-FEC 2020 2021/5/10-15 IAEA-FEC 2020 1 CONTENTS 1. Introduction Objectives of the LHD Deuterium Experiment LHD (Large Helical Device) 2. Recent achievements and activities at D- exp. Extension in temperature domain Isotope Effect and Isotope related studies RMP induced H-mode 3. SUMMARY 2021/5/10-15 IAEA-FEC 2020 2 CONTENTS 1. Introduction Objectives of the LHD Deuterium Experiment LHD (Large Helical Device) 2. Recent achievements and activities at D- exp. Extension in temperature domain Isotope Effect and Isotope related studies RMP induced H-mode 3. SUMMARY 2021/5/10-15 IAEA-FEC 2020 3 Objective of Deuterium Experiment 1. Realization of high-performance plasmas by confinement improvement and by the improved heating devices and other facilities ⇒ Extend the operational region of LHD to the reactor relevant plasmas 2. Exploration of the isotope effect study in plasma confinement Isotope effect is long underlying mystery in plasma physics ⇒ The information of isotope effect in helical system will lead to the comprehensive understanding on plasma physics 3. Demonstration of the confinement capability of energetic particles (EPs) in helical system and exploration of their confinement studies ⇒ Perspective understanding on EP physics for burning plasmas will be provided for toroidal plasmas 4. Extended studies on Plasma-Wall Interactions (PWI) and tritium retention studies 2021/5/10-15 IAEA-FEC 2020 4 LHD (Large Helical Device) One of the largest superconducting machine in the world Specifications Mode numbers : l/M=2/10 All superconducting system helical coils, poloidal coils and bus lines Plasma major radius: 3.55-4.1 m Plasma minor radius: ~0.6 m Plasma volume: 30 m3 Toroidal field strength: 3 T 10 pairs of RMP coils March 31st, 1998 1st plasma March 7th , 2017 Deuterium Experiment 2021/5/10-15 IAEA-FEC 2020 5 Heating System on LHD Negative- Positive- NBI NBI Heating Systems Negative-NBI (tangential)x 3 (180- 190keV), Negative- H16MW, D8MW NBI ECH 77GHz x2 154GHz x2 Positive-NBI (radial) x 2 (40-80keV), H12MW, D18MW Negative- NBI ICH x2 ECH (77GHz x 3, 154GHz x 2, 56GHz) 5.5MW ECH 77GHz x1 ICH (38.47MHz) x 2 2 MW 56GHz x1 Positive- NBI 2021/5/10-15 IAEA-FEC 2020 6 N-NBI improvement for LHD has been demonstrated the reliable D-operation ⇒ Tsumori, K. (ID: 763) operation of Negative-ion based for more N-NBI optics than 20 years. ⇒ Kisaki, M. (ID:734 ) It was proved that the specification of ITER-NBI can be fulfilled simultaneously using negative-ion source at the real operation for plasma injection. 20 ITER-NBI LHD-NBI N-NBI x2 N-NBI x3 2 2 JH- > 260A/m 340 A/m LHD-NBI 5MW/NBI (H) Ie/IH- <1 0.25 15 specification div. 3-7mrad 5mrad 10 N-NBI(MW) 5 0 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2015 2017 2018 2019 2020 Year 2021/5/10-15 IAEA-FEC 2020 7 CONTENTS 1. Introduction Objectives of the LHD Deuterium Experiment LHD (Large Helical Device) 2. Recent achievements and activities at D- exp. Extension in temperature domain Isotope Effect and Isotope related studies RMP induced H-mode 3. SUMMARY 2021/5/10-15 IAEA-FEC 2020 8 Expansion in Temp.: Extension of high-temperature regime ⇒ Takahashi, H. (ID:781) EIC suppression: From previous FEC: ⇒ Ohdachi, S. (ID:800) The operation regime with the simultaneous high Ti and high Te EIC effect on EP: was successfully extended. ⇒ Ogawa, K. (ID: 688) It was found; • The EP driven resistive InterChange mode (EIC) should be NBI: ~30 MW, suppressed to avoid the loss of EPs to increase the ion ECH: 4 MW, -> High Te/Ti, temperature and can be suppressed by increasing Te. Low dTi/dreff •TheratioofT /T should be kept below 0.75 to keep NBI: ~30 MW, 16 e i (b) better ion thermal confinement property. ECH: ~1 MW, -> No EICs, 14 #157822 ⇒ Moderate ECH heating is important in extending the TS: 4.717 s Mid. Te/Ti CXS: 4.73 s parameter. 12 12 4 MW ECRH T (a) i T (a) 10 #150133 10 e 10 9.45 s ~FEC FEC2018 2018 1 MW ECRH ~Present 6 8 8 Hydrogen 8 (b) Deuterium 6 6 6 i T 4 T T e i L [keV] / i0 r = 0.1 m 4 4 R T 4 eff 2 n 2 n 2 e 2 ~FEC e 2016 0 0 0 0 0 0.2 0.4 0.6 024681012 0 0.5 1 1.5 2 2.5 3 00.20.40.6 T [keV] T/T r [m] r [m] e0 e i eff eff 9 2021/5/10-15 IAEA-FEC 2020 CONTENTS 1. Introduction Objectives of the LHD Deuterium Experiment LHD (Large Helical Device) 2. Recent achievements and activities at D- exp. Extension in temperature domain Isotope Effect and Isotope related studies RMP induced H-mode 3. SUMMARY 2021/5/10-15 IAEA-FEC 2020 10 Yamada, H. (ID:718) Isotope Effect for L-mode plasma • The existence of Mass dependence in addition gyro-Bohm nature was confirmed using H, D, He, and their mixture L- mode dimensionally similar plasmas. Dimensionless energy confinement time scaling with 4 dimensionless parameter, i.e., M, *,*, . . ∗. ∗. Ω ∝ ∗ Gyro-Bohm nature: Ω ∝ . 2021/5/10-15 IAEA-FEC 2020 11 Yamada, H. (ID:718) The local thermal transport property is also investigated for dimensionally similar plasmas An improvement in e/i for D plasmas is found especially for high collisional region of * >0.2. On the other hand, the difference in i/i is less significant. 2021/5/10-15 IAEA-FEC 2020 12 Kobayashi, T. (ID: 832) Isotope effects of the plasmas with internal transport barrier (ITB) are investigated defineing an ITB intensity • ITB intensity is a measure: “How much T profile deviates from D i the LHD L-mode scaling (∝)” T. Kobayashi+, Plasma Phys. Control. Fusion 61 085005 (2019) ITB intensity H • ITB intensity in D is larger than that 19 -3 in H when / > 4 MW/10 m . T. Kobayashi+, Sci. Rep. 9 15913 (2019) ITB • Principal component analysis intensity reveals that ITB becomes stronger when both / and are simultaneously large. • Radial electric field shear plays a minor role. 2021/5/10-15 IAEA-FEC 2020T. Kobayashi+, this conference (CN-832) 13 Control of isotope fraction (D/(D+T) ratio) is a crucial issue Ida, K. (ID: 692) for the control of the fusion power in future reactors. Investigation of hydrogen isotopes behavior in their mixture plasmas is important. A theoretical paper by Bourdelle (NF2018) suggests the isotope mixing state appears at ITG dominant plasmas and non-mixing state does at TEM dominant plasmas. ⇒ Isotope mixing/non-mixing plasmas are observed in LHD. Phase Contrast Imaging (PCI) (a) (e) Mixing state Low frequency peak Non-mixing state (b) High frequency peak (f) (c) GKV Simulation shows Low frequency peak for ITG mode and (d) High frequency peak (g) for TEM 6 2021/5/10-15 IAEA-FEC 2020 14 CONTENTS 1. Introduction Objectives of the LHD Deuterium Experiment LHD (Large Helical Device) 2. Recent achievements and activities at D- exp. Extension in temperature domain Isotope Effect and Isotope related studies RMP induced H-mode 3. SUMMARY 2021/5/10-15 IAEA-FEC 2020 15 New improved confinement regime, Kobayashi, M. (ID: 837) “RMP induced H-mode”, was found in LHD Improved mode Density was lamped up during the discharge. Detach ) Stable sustainment of the divertor -3 m 10 e nsudo n detachment is realized by an RMP 19 5 application. (10 0 Significant reduction in Div. flux. 2 NBI (MW) 4 Prad. reaches ~60% of Pheat. 1 rad (MW) The improvement of confinement observed P 0 0 at the onset of the detachment and the 300 (kJ) 200 Edge Transport Barrier (ETB) was formed. dia p 100 Further improvement in confinement was W 0 observed during the detached phase. 0.1 ⇒ RMP induced H-mode flux (A) Div particle 0 101 12 3-30 kHz Improved mode 100 (detach) 10 -1 30-150 kHz 4.9 sec 10 (a.u.) ) Density 3 8 -2 fluctuation 10 150-500 kHz 6 Detach ETB 33.544.555.5 4.3 sec (kJ/m Time [s] e 4 P 2 Attach 3.8 sec Simultaneous achievement of reduced divertor 0 heat load and good core confinement 2.83.23.64.04.44.8 R(m) 2021/5/10-15 IAEA-FEC 2020 16 An application of RMP(m/n=1/1) is the key to Kobayashi, M. (ID: 837) maintain stable divertor detachment. The stochastic region Te<~20eV expanded by the RMP enhances the radiation by carbon impurities at the peripheral. Steep gradient in Lc might play an important role in the stable sustainment of the radiative region. 2021/5/10-15 IAEA-FEC 2020 Kobayashi, M. et al. 17 An Improved confinement Kobayashi, M. (ID: 837) after detachment is observed The reduction of an impurity line intensity (CVI) is also observed at the onset of the improved confinement The triggering mechanism of the improved confinement transition is not understood, yet. The impurity behavior might play a role at the triggering event. 2021/5/10-15 IAEA-FEC 2020Kobayashi, M. et al. 18 SUMMARY The extension of high temperature domain significant in the deuterium experiment. Ti0=10.6keV&Te0=5.6keV, Ti0=6.8keＶ & Te0=12.7keV achieved, simultaneously. The suppression of EIC is the key to extend the domain • The EIC can be suppressed by ECH The Te/Ti ratio is better to be kept below 0.75 to obtain good ion confinement.
Load more

Recommended publications
  • STATUS of FUSION ENERGY Impact & Opportunity for Alberta Volume II
    STATUS OF FUSION ENERGY Impact & Opportunity for Alberta Volume II Appendices Prepared by Alberta/Canada Fusion Energy Program March 2014 ALBERTA COUNCIL OF TECHNOLOGIES Gratefully acknowledges the support of: Alberta Energy Stantec Corporation University of Alberta Alberta/Canada Fusion Energy Advisory Committee Gary Albach Nathan Armstrong Brian Baudais Will Bridge Robert Fedosejevs Peter Hackett Chris Holly Jerry Keller Brian Kryska Axel Meisen Rob Pitcairn Klaas Rodenburg John Rose Glenn Stowkowy Martin Truksa Gary Woloshyniuk Perry Kinkaide Allan Offenberger A special thank you is extended to the institutions (identified in this report) that were visited and to the many persons who so graciously hosted our site visits, provided the briefing material presented in this status report and thereby assisted our fusion assessment. Report Authors Allan Offenberger Robert Fedosejevs Klaas Rodenburg Perry Kinkaide Contact: Dr. Perry Kinkaide [email protected] 780-990-5874 Dr. Allan Offenberger [email protected] 780-483-1740 i TABLE OF CONTENTS Page List of Acronyms ………………………………………………………………………….. iii List of Figures……………………………………………………………………………… iv Appendix A: Assessment of Major Global Fusion Technologies 1.0 Context - Global Energy Demand……………………………………………………… 1 1.0.1 Foreward ……………………………………………………………………… 1 1.0.2 Energy Trends………………………………………………………………… 2 1.0.3 Energy From Fusion Reactions……………………………………………… 4 1.1 Major Approaches to Fusion Energy………………………………………………….. 7 1.1.1 Introduction……………………………………………………………………. 7 1.1.2 Fusion Reactions & the Fuel Cycle………………………………………….. 8 1.1.3 IFE Approaches to Fusion…………………………………………………… 11 1.1.3.1 Introduction………………………………………………………….. 11 1.1.3.2 Indirect Drive…………………………………………………………14 1.1.3.3 Direct Drive…………………………………………………………. 16 1.1.3.4 Fast Ignition………………………………………………………… 17 1.1.3.5 Shock Ignition………………………………………………………..19 1.1.3.6 IFE Power Reactor Systems……………………………………….20 1.1.3.7 Modeling Codes…………………………………………………….
    [Show full text]
  • Significance of MHD Effects in Stellarator Confinement
    Ms-313705 Final Paper Significance of MHD Effects in Stellarator Confinement A. Weller1, S. Sakakibara2, K.Y. Watanabe2, K. Toi2, J. Geiger1, M.C. Zarnstorff3, S.R. Hudson3, A. Reiman3, A. Werner1, C. Nührenberg1, S. Ohdachi2, Y. Suzuki2, H. Yamada2, W7-AS Team1, LHD Team2 1Max-Planck-Institut für Plasmaphysik, EURATOM-IPP Association, D-17491 Greifswald, Germany 2National Institute for Fusion Science, Toki 509-5292, Japan 3Princeton Plasma Physics Laboratory, Princeton, NJ 08543, USA Corresponding Author: Dr. Arthur Weller ( [email protected] ) Max-Planck-Institut für Plasmaphysik, EURATOM-IPP Association, Wendelsteinstr. 1, D-17491 Greifswald, Germany Fax: +49 (0)3834 88 2509 Content of Paper: Main Text: 27 pages (including references and figure captions) 12 Figures, no Table - 1 - Ms-313705 Final Paper Abstract Substantial progress has been achieved to raise the plasma beta in stellarators and helical systems by high power neutral beam heating, approaching reactor relevant values [1-3]. The achievement of high-β operation is closely linked with configuration effects on the confinement and with magnetohydrodynamic (MHD) stability. The magnetic configurations of the Wendelstein W7-AS stellarator and of the Large Helical Device (LHD) and their optimization for high-β operation within the flexibility of the devices are characterized. A comparative description of the accessible operational regimes in W7-AS and LHD is given. The finite-β effects on the flux surfaces depend on the degree of configuration optimization. In particular, a large Shafranov shift is accompanied by formation of islands and stochastic field regions as found by numerical equilibrium studies [2,4]. However, the observed pressure gradients indicate some mitigation of the effects on the plasma confinement, presumably because of the high collisionality of high-β plasmas and island healing effects (LHD [5-7]).
    [Show full text]
  • An Unreal Reality Pushes Fusion Science Jet – the Most Successful Performance in Years How to Tame Plasma Turbulence
    FUSION IN EUROPE NEWS & VIEWS ON THE PROGRESS OF FUSION RESEARCH AN UNREAL REALITY PUSHES FUSION SCIENCE JET – THE MOST SUCCESSFUL PERFORMANCE IN YEARS HOW TO TAME PLASMA TURBULENCE 4 2016 FUSION IN EUROPE 4 2016 Contents Delphine Keller from EURO­ fusion’s French Research Unit Moving Forward CEA is dressed for a jump into the virtual fusion world. Glas­ 3 A European fusion programme to be proud of ses, immersive headsets and motion trackers allow her to 4 The most successful performance in years study the interior of a tokamak. Picture: CEA 6 An unreal reality pushes fusion science 10 IAEA awards EUROfusion’s work 12 Impressions Research Units 14 COMPASS has changed its point of view 18 How to tame plasma turbulence 18 21 Mix it up! The simulation of electrostatic potential along 22 News the torus lines inside a fusion experiment. These experiments help to find origins of plasma turbulence.. Community Picture: GYRO/General Atomics 24 Supernovae in the lab – powered by EUROfusion 28 Pushing the science beyond fusion 30 Young faces of fusion – Robert Abernethy 12 Fuel for Thought Who says operators at the Czech tokamak 33 Combining Physics and Management Forces COMPASS don’t have a sense Perspectives of humour? – More amusing details from fusion on page 12 and 13. 34 Summing Up Picture: EUROfusion EUROfusion © Tony Donné (EUROfusion Programme Manager) Imprint Programme Management Unit – Garching 2016. FUSION IN EUROPE Boltzmannstr. 2 This newsletter or parts of it may not be reproduced ISSN 1818­5355 85748 Garching / Munich, Germany without permission. Text, pictures and layout, except phone: +49-89-3299-4128 where noted, courtesy of the EUROfusion members.
    [Show full text]
  • Present Status of Research Activities at the National Institute for Fusion
    PRESENT STATUS OF RESEARCH ACTIVITIES AT THE XA9745749 NATIONAL INSTITUTE FOR FUSION SCIENCE AND ITS ROLE IN INTERNATIONAL COLLABORATION J. FUJITA National Institute for Fusion Science, Nagoya, Japan Abstract In the National Institute for Fusion Science (NIFS), Japan, a helical magnetic confinement system named Large Helical Device (LHD) is under construction with objectives of comprehensive studies of high temperature plasmas in a helical system and investigation of a helical reactor as an alternative approach. Superconducting coils ofl = 2,m= 10, major radius R = 3.9 m, produce a steady state helical magnetic field for confinement, together with poloidal coils on LHD. The magnetic field strength on the axis is 3.0 T in the phase I and 4.0 T in the phase II experiment. The plasma major radius of LHD is 3.75 m, and averaged plasma radius is 0.6 m. The plasma will be produced and heated with ECH, and further heated with NBI and ICRF. It is also planned to produce a steady state plasma in LHD. It is expected to have the first plasma in 1998. Small devices such as CHS and others are under operation in the NIFS for supporting the LHD project. The Data and Planning Center of NIFS is collecting, compiling and evaluating atomic and molecular data which are necessary for nuclear fusion research. The talk will include the present status of the construction of LHD, research activities on the development of heating and diagnostic devices for LHD, and experimental results obtained on CHS, JIPP T-IIU and other devices. The role of NIFS on promoting IAEA activities to bridge large scale institutions and small and medium scale laboratories for world-wide collaborations in the field of plasma physics and fusion research will also be introduced, together with an idea of organizing a regional center in Asia.
    [Show full text]
  • Nuclear Fusion Power – an Overview of History, Present and Future
    International Journal of Advanced Network, Monitoring and Controls Volume 04, No.04, 2019 Nuclear Fusion Power – An Overview of History, Present and Future Stewart C. Prager Department of Physics University of Wisconsin – Madison Madison, WI 53706, USA E-mail: [email protected] Summary—Fusion power offers the prospect of an allowing the nuclei to fuse together. Such conditions almost inexhaustible source of energy for future can occur when the temperature increases, causing the generations, but it also presents so far insurmountable ions to move faster and eventually reach speeds high engineering challenges. The fundamental challenge is to enough to bring the ions close enough together. The achieve a rate of heat emitted by a fusion plasma that nuclei can then fuse, causing a release of energy. exceeds the rate of energy injected into the plasma. The main hope is centered on tokamak reactors and II. FUSION TECHNOLOGY stellarators which confine deuterium-tritium plasma In the Sun, massive gravitational forces create the magnetically. right conditions for fusion, but on Earth they are much Keywords-Fusion Energy; Hydrogen Power; Nuclear Fusion harder to achieve. Fusion fuel – different isotopes of hydrogen – must be heated to extreme temperatures of I. INTRODUCTION the order of 50 million degrees Celsius, and must be Today, many countries take part in fusion research kept stable under intense pressure, hence dense enough to some extent, led by the European Union, the USA, and confined for long enough to allow the nuclei to Russia and Japan, with vigorous programs also fuse. The aim of the controlled fusion research underway in China, Brazil, Canada, and Korea.
    [Show full text]
  • 1 Overview of JT-60U Progress Towards Steady-State Advanced Tokamak
    1 OV/1-1 Overview of JT-60U Progress towards Steady-state Advanced Tokamak S. Ide and the JT-60 Team Naka Fusion Research Establishment Japan Atomic Energy Research Institute Naka-machi, Naka-gun, Ibaraki, 311-0193 Japan e-mail contact of main author: [email protected] Abstract. Recent experimental results on steady state advanced tokamak (AT) research on JT-60U are presented with emphasis on longer time scale in comparison with characteristics time scales in plasmas. Towards this, modification on control in operation, heating and diagnostics systems have been done. As the results, ∼ 60 s Ip flat top and an ∼ 30 s H-mode are obtained. The long pulse modification has opened a door into a new domain for JT-60U. The high normalized beta (β N)of2.3 is maintained for 22.3 s and 2.5 for 16.5 s in a high β p H-mode plasma. A standard ELMy H-mode plasma is also extended and change in wall recycling in such a longer time scale has been unveiled. Development and investigation of plasmas relevant to AT operation has been continued in former 15 s discharges as well in which higher NB power ( 10 s) is available. Higher β N ∼ 3 is maintained for 6.2 s in high βp H-mode plasmas. High bootstrap current fraction (f BS)of∼ 75% is sustained for 7.4 s in an RS plasma. On NTM suppression by localized ECCD, ECRF injection preceding the mode saturation is found to be more effective to suppress the mode with less power compared to the injection after the mode saturated.
    [Show full text]
  • Density Limit Studies in the Large Helical Device
    JP0555011 Density Limit Studies in the Large Helical Device B. J. Peterson, J. Miyazawa, K. Nishimura, S. Masuzaki, Y. Nagayama, N. Ohyabu, H. Yamada, K. Yamazaki, T. Kato, N. Ashikawa, Yuhong Xu1, A. Yu. Kostrioukov2, Yi Liu3, R. Sakamoto, M. Goto, K. Narihara, M. Osakabe, K. Tanaka, T. Tokuzawa, M. Shoji, H. Funaba, S. Morita, T. Morisaki, O. Kaneko, K. Kawahata, A. Komori, S. Sudo, O. Motojima and the LHD Experiment Group National Institute for Fusion Science, Toki-shi, Gifu-ken 509-5292 JAPAN 'Forschungszentrum Juelich, Juelich, Germany 2St. Petersburg Technical University, St. Petersburg, Russia 3 Southwest Institute of Physics, Chengdu, China e-mail contact of main author: peterson(S>LHD.nifs.ac.ip PACS 52.55.Hc, 52.25.Vy, 52.25.Fi Abstract. Steady state densities of up to 1.6 x 1020m3 have been sustained using gas puff fuelling and NBI heating up to 11 MW in the Large Helical Device (LHD). The density limit in LHD is observed to be ~ 1.6 times the Sudo limit The density is ultimately limited by radiative collapse which is attributed to the onset of a radiative thermal instability of the light impurities in the edge region of the plasma based on several observations. First of all the onset of the radiative thermal instability is tied to a certain edge temperature threshold. Secondly, the onset of thermal instability occurs first in oxygen and then carbon as expected from their cooling rate temperature dependencies. Finally, radiation profiles show that as the temperature drops and the plasma collapses the radiating zone broadens and moves inward.
    [Show full text]
  • Review of Stellarator Research: in Search of the "Magic Magnetic Bottle"
    -Tt» «MM mna im oma [ REVIEW OF STELLARATOR RESEARCH: IN SEARCH OF THE "MAGIC MAGNETIC BOTTLE" NICOLAS DOMINGUEZ CCNF-920728-2 Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, 77V 37831-8071, USA DE92 019045 ABSTRACT We summarize the current work on stellarators being carried out out in fusion research laboratories around the world. The theoretical aspects of the stellarator research are emphasized. *'~ 1. Introduction The steadily increasing need for energy makes it imperative to look for new sources of energy for the future. Fusion energy is one of the most promising posibilities. One of the main approaches to harnessing fusion energy is magnetic confinement. In this approach, the thermonuclear plasma containing the fuel to be fused is confined in a magnetic trap, where it can be heated to the high temperatures necessary for nuclear processes to occur1. Confining a plasma involves the creation of gradients of density, temperature and pressure. The presence of those gradients implies the creation of free energies. These free energies have the potential to destroy the magnetic confinement through magnetohydrodynamic (MHD) instabilities and microinstabilities. The central issue for magnetic confinement is to create a magnetic bottle that confines the plasma in such a way that the free energies are not too dangerous for confinement. It is fair to say that the history of fusion research for more than 30 years has been the search for a "magic magnetic bottle" -one with excellent confinement properties at low cost. A number of concepts have been developed as part of this search. Among them we can list the Model C stellarator, the mirror machines, the pinches, the tandem mirrors, the bumpy torus, the reversed-fisld pinches (RFPs), the tokamaks, the spherical tokamaks, and the advanced stellarators.
    [Show full text]
  • The Fairy Tale of Nuclear Fusion L
    The Fairy Tale of Nuclear Fusion L. J. Reinders The Fairy Tale of Nuclear Fusion 123 L. J. Reinders Panningen, The Netherlands ISBN 978-3-030-64343-0 ISBN 978-3-030-64344-7 (eBook) https://doi.org/10.1007/978-3-030-64344-7 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland When you are studying any matter or considering any philosophy, ask yourself only what are the facts and what is the truth that the facts bear out.
    [Show full text]
  • 1. Large Helical Device (LHD) Project
    1. Large Helical Device (LHD) Project The Large Helical Device (LHD) project conducts fusion-grade confinement research in a steady-state ma- chine to elucidate important research issues in physics and engineering for the helical-type fusion reactor. The LHD is one of the largest helical devices, with poloidal/toroidal period numbers of 2/10, and major and averaged plasma minor radius of 3.6 – 4.0 m and 0.6 m, respectively. A double helical coil and three pairs of poloidal coils are all superconducting, by which maximum magnetic field strength at the plasma center is 3 T. Twenty small normal conducting loop coils are equipped outside the cryostat to apply resonant magnetic perturbations to the plasma. For plasma heating, three negative-ion-based 180 – 190 keV neutral beams with total heating power of 8 – 16 MW are injected tangentially to the plasma. Two positive-ion- based 40 – 80 keV neutral beams with total heating power of 6 – 18 MW are also injected perpendicular to the plasma. In addition, electron cyclotron resonance heating with total heating power of ~ 5.5 MW is also available. For fuelling, LHD is equipped with four gas puff valves and two pellet injectors. Fig. 1 (a) Coil configuration of LHD. Superconducting helical coils (blue), poloidal coils (yellow) and normal conducting RMP coils, together with plasma. (b) LHD torus hall. 1 In experiments conducted to date in tokamak devices, we have learned that plasma confinement perfor- mance is better in deuterium than in hydrogen, which is called the “isotope effect.” However, we do not yet understand clearly why plasma performance increases when we change the gas from hydrogen to deuterium.
    [Show full text]
  • Three-Dimensional Stellarator Codes
    Three-dimensional stellarator codes P. R. Garabedian* Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, NY 10012 Contributed by P. R. Garabedian, June 3, 2002 Three-dimensional computer codes have been used to develop anomalous transport can be modeled by iterating on small quasisymmetric stellarators with modular coils that are promising variations of the electric potential within the magnetic surfaces candidates for a magnetic fusion reactor. The mathematics of to achieve quasineutrality between the distributions of ions and plasma confinement raises serious questions about the numerical electrons. The method simulates complicated transport in stel- calculations. Convergence studies have been performed to assess larators remarkably well, and numerical results have been ob- the best configurations. Comparisons with recent data from large tained for the large helical device (LHD) experiment at the stellarator experiments serve to validate the theory. National Institute for Fusion Studies in Toki, Japan that are in excellent agreement with recent observations of the energy odular stellarators can be viewed as an advanced tokamak confinement time at high temperatures (6, 7). A vectorized Mhybrid appropriate for implementation as a fusion reactor version of the TRAN code runs efficiently on standard work (1). Quasisymmetry of the magnetic spectrum is predicted to stations. give good confinement at high temperatures, and adequate Convergence Studies rotational transform from the external magnetic field is expected to stabilize the plasma. New configurations have been designed Calculation of toroidal equilibrium of a plasma without two- by making imaginative use of three-dimensional computer codes. dimensional symmetry is a problem in mathematics that is not Because the mathematics of these stellarators is complicated, we well posed.
    [Show full text]
  • Overview of JT-60U Progress Towards Steady-State Advanced Tokamak
    20th IAEA Fusion Energy Conference Vilamoura, Portugal, 1-6 November 2004 ________________________________________________________________________ IAEA-CN-116/OV/1-1 Overview of JT-60U Progress towards Steady-state Advanced Tokamak S. Ide and the JT-60 Team Naka Fusion Research Establishment Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki, 311-0193 Japan _______________________________________________________________________________________ This is a preprint of a paper intended for presentation at a scientific meeting. Because of the provisional nature of its content and since changes of substance or detail may have to be made before publication, the preprint is made available on the understanding that it will not be cited in the literature or in any way be reproduced in its present form. The views expressed and the statements made remain the responsibility of the named author(s); the views do not necessarily reflect those of the government of the designating Member State(s) or of the designating organization(s). In particular, neither the IAEA nor any other organization or body sponsoring this meeting can be held responsible for any material reproduced in this preprint. 1 OV/1-1 Overview of JT-60U Progress towards Steady-state Advanced Tokamak S. Ide and the JT-60 Team Naka Fusion Research Establishment Japan Atomic Energy Research Institute Naka-machi, Naka-gun, Ibaraki, 311-0193 Japan e-mail contact of main author: [email protected] Abstract. Recent experimental results on steady state advanced tokamak (AT) research on JT-60U are presented with emphasis on longer time scate in comparison with characteristics time scales in plasmas. Towards this, modification on control in operation, heating and diagnostics systems have been done.
    [Show full text]