Progress of the Keda Torus eXperiment Project in China: design and mission

The Keda Torus eXperiment (KTX) is a medium-sized reversed field pinch (RFP) device under construction at the University of Science and Technology of China. The KTX has a major radius of 1.4 m and a minor radius of 0.4 m with an Ohmic discharge current up to 1 MA. The expected electron density and temperature are, respectively, 2 × 1019 m−3 and 800 eV. A combination of a stainless steel vacuum chamber and a thin copper shell (with a penetration time of 20 ms) surrounding the plasma provides an opportunity for studying resistive wall mode instabilities. The unique double-C design of the KTX vacuum vessel allows access to the interior of the KTX for easy first-wall modifications and investigations of power and particle handling, a largely unexplored territory in RFP research leading to demonstration of the fusion potential of the RFP concept. An active feedback mode control system is designed and will be implemented in the second phase of the KTX program. The recent progress of this program will be presented, including the design of the vacuum vessel, magnet systems and power supplies.

[1]  R. C. Wolf,et al.  Internal transport barriers in tokamak plasmas , 2003 .

[2]  P. Brunsell,et al.  Coherent magnetic field fluctuations and locked modes in a reversed-field pinch , 1993 .

[3]  W. A. Cooper,et al.  Overview of the RFX-mod fusion science programme , 2012 .

[4]  L. Marrelli,et al.  Vanishing magnetic shear and electron transport barriers in the RFX-mod reversed field pinch. , 2011, Physical review letters.

[5]  B. E. Chapman,et al.  Overview of quasi-single helicity experiments in reversed field pinches , 2003 .

[6]  R. M. Magee,et al.  Improved-confinement plasmas at high temperature and high beta in the MST RFP , 2009 .

[7]  Physics of strong internal transport barriers in JT-60U reversed-magnetic-shear plasmas , 2006 .

[8]  S. Munaretto,et al.  The plasma boundary in single helical axis RFP plasmas , 2009, 0909.3011.

[9]  K. Ida.  Transport barriers in non-axisymmetric magnetic fields , 2008 .

[10]  J. Drake,et al.  Current profile modification experiments in EXTRAP T2R , 2004 .

[11]  Murari,et al.  Quasi-single-helicity reversed-field-pinch plasmas , 2000, Physical review letters.

[12]  Sergio Ortolani,et al.  Experimental and theoretical studies of active control of resistive wall mode growth in the EXTRAP T2R reversed-field pinch , 2004 .

[13]  A. Murari,et al.  CORE TRANSPORT IMPROVEMENT DURING POLOIDAL CURRENT DRIVE IN THE RFX REVERSED FIELD PINCH , 1999 .

[14]  P. Nordlund,et al.  Nonlinear dynamics of kink‐tearing modes and their interaction with the current profiles in a reversed‐field pinch , 1994 .

[15]  L. Frassinetti,et al.  Operating Conditions to Achieve High Performance in PPCD in a Reversed-Field Pinch Plasma , 2003 .

[16]  S. Hirshman,et al.  Three-dimensional equilibria and transport in RFX-mod: A description using stellarator toolsa) , 2010 .

[17]  Y. Yagi,et al.  Improved confinement in the TPE-RX RFP by means of the PPCD , 2002 .

[18]  D. J. Holly,et al.  Overview of results in the MST reversed field pinch experiment , 2005 .

[19]  N. Lanier,et al.  Increased confinement and β by inductive poloidal current drive in the reversed field pinch , 1997 .

[20]  L. Lao,et al.  Non-axisymmetric equilibrium reconstruction for stellarators, reversed field pinches and tokamaks , 2013 .

[21]  Marco Cecconello,et al.  Initial results from the rebuilt EXTRAP T2R RFP device , 2001 .

[22]  H. Shimazu,et al.  Characterization of Initial Low-Aspect Ratio RFP Plasmas in "RELAX"(Gases, plasmas, electric discharges, and beams) , 2007 .

[23]  L. Marrelli,et al.  Improved confinement with internal electron transport barriers in RFX-mod , 2009 .

[24]  A. Murari,et al.  Quasi-single helicity states in the reversed field pinch: Beyond the standard paradigm , 2000 .

[25]  Tomonori Takizuka.  11th IAEA Technical Meeting on H-mode Physics and Transport Barriers , 2008 .

[26]  Comparison of particle transport properties in TPE-RX standard and PPCD plasmas , 2009 .

[27]  G. Manduchi,et al.  RWM control studies on RFX-mod with a limited set of active coilsThis paper was an intended contribution to the special issue on MHD control in burning plasmas (iopscience.iop.org/0029-5515/52/7). , 2012 .

[28]  L. Apolloni,et al.  Internal and external electron transport barriers in the RFX-mod reversed field pinch , 2011 .

[29]  L. Frassinetti,et al.  Controlled Resonant Magnetic Perturbation Physics Studies on EXTRAP T2R , 2011 .

[30]  R. Paccagnella,et al.  Nonlinear plasma evolution and sustainment in the reversed field pinch , 1992 .

[31]  A. Luchetta,et al.  Advanced MHD mode active control at RFX-mod , 2009 .

[32]  F L Tabarés,et al.  Tritium inventory control during ITER operation under carbon plasma-facing components by nitrogen-based plasma chemistry: a review , 2013 .

[33]  X. Duan,et al.  Experiment of non-local effect with SMBI on HL-2A , 2010 .

[34]  R. Paccagnella,et al.  Single helicity: a new paradigm for the reversed field pinch , 2000 .

[35]  L. Giudicotti,et al.  Helical equilibria and magnetic structures in the reversed field pinch and analogies to the tokamak and stellarator , 2009 .

[36]  David R. Smith,et al.  Suppressing Electron Turbulence and Triggering Internal Transport Barriers with Reversed Magnetic Shear in the National Spherical Torus Experiment , 2012 .

[37]  T. Bolzonella,et al.  Spontaneous and driven reduced turbulence modes in the RFX reversed field pinch , 1999 .

[38]  Stewart C. Prager,et al.  Experimental scaling of fluctuations and confinement with Lundquist number in the reversed-field pinch , 1998 .

[39]  F. Bellina,et al.  The RFX magnet system , 1995 .

[40]  Piero Martin,et al.  Magnetic and thermal relaxation in the reversed field pinch , 1999 .

[41]  A. A. Newton,et al.  Reversed-field-pinch research , 1980 .

[42]  D. Schnack,et al.  Effect of aspect ratio on magnetic field fluctuations in the reversed-field pinch , 1995 .

[43]  F. Milani,et al.  Self-organized helical equilibria as a new paradigm for ohmically heated fusion plasmas , 2009 .

[44]  S. Cappello.  Bifurcation in the MHD behaviour of a self-organizing system: the reversed field pinch (RFP) , 2004 .

[45]  K. Werley.  Reversed field pinch ignition requirements , 1991 .

[46]  K J McCollam,et al.  Oscillating-field current-drive experiments in a reversed field pinch. , 2006, Physical review letters.

[47]  Sergio Ortolani,et al.  Active MHD control experiments in RFX-mod , 2006 .

[48]  James R. Drake,et al.  Resistive wall mode feedback control in EXTRAP T2R with improved steady-state error and transient response , 2007 .