Experimental verification of sawtooth control by energetic particles in ion cyclotron resonance heated JET tokamak plasmas

Experimental evidence from the JET tokamak is presented supporting the predictions of a recent theory (Graves et al 2009 Phys. Rev. Lett. 102 065005) on sawtooth instability control by toroidally propagating ion cyclotron resonance waves. Novel experimental conditions minimized a possible alternate effect of magnetic shear modification by ion cyclotron current drive, and enabled the dependence of the new energetic ion mechanism to be tested over key variables. The results have favourable implications on sawtooth control by ion cyclotron resonance waves in a fusion reactor.

[1]  Torbjörn Hellsten,et al.  The influence of finite drift orbit width on ICRF heating in toroidal plasmas , 2002 .

[2]  R J Buttery,et al.  Destabilization of fast-ion-induced long sawteeth by localized current drive in the JET tokamak. , 2004, Physical review letters.

[3]  M. Rosenbluth,et al.  Model for the sawtooth period and amplitude , 1996 .

[4]  J. Graves.  Influence of asymmetric energetic ion distributions on sawtooth stabilization. , 2004, Physical review letters.

[5]  Olivier Sauter,et al.  Effects of localized electron heating and current drive on the sawtooth period , 2003 .

[6]  N. R. Sauthoff,et al.  Studies of internal disruptions and m=1 oscillations in tokamak discharges with soft--X-ray techniques , 1974 .

[7]  E. D. Fredrickson,et al.  Ion cyclotron range of frequencies stabilization of sawteeth on Tokamak Fusion Test Reactor , 1992 .

[8]  T Johnson,et al.  Sawtooth-control mechanism using toroidally propagating ion-cyclotron-resonance waves in tokamaks. , 2009, Physical review letters.

[9]  Nathaniel J. Fisch,et al.  Theory of current-drive in plasmas , 1987 .

[10]  D. J. Campbell,et al.  Chapter 1: Overview and summary , 1999 .

[11]  T. Hellsten,et al.  Modelling of minority ion cyclotron current drive during the activated phase of ITER , 2005 .

[12]  Herbert L Berk,et al.  The HAGIS self-consistent nonlinear wave-particle interaction model , 1998 .

[13]  R. Carrera,et al.  Island bootstrap current modification of the nonlinear dynamics of the tearing mode , 1986 .

[14]  F Turco,et al.  Demonstration of effective control of fast-ion-stabilized sawteeth by electron-cyclotron current drive. , 2009, Physical review letters.

[15]  Bhatnagar,et al.  Stabilization of sawteeth with additional heating in the JET tokamak. , 1988, Physical review letters.

[16]  P. Cochat,et al.  Et al , 2008, Archives de pediatrie : organe officiel de la Societe francaise de pediatrie.

[17]  Francesco Porcelli,et al.  Local magnetic shear control in a tokamak via fast wave minority ion current drive : theory and experiments in jet , 1994 .

[18]  Carlsson,et al.  Minority ion cyclotron current drive in tokamaks. , 1995, Physical review letters.

[19]  O. Sauter,et al.  Control of neoclassical tearing modes by sawtooth control. , 2002, Physical review letters.

[20]  T. H. Stix.  Fast-wave heating of a two-component plasma , 1975 .

[21]  White,et al.  Sawtooth stabilization by energetic trapped particles. , 1988, Physical review letters.

[22]  Jet Efda Contributors,et al.  Sawtooth control using off-axis NBI , 2008 .

[23]  P. T. Bonoli,et al.  Sawtooth period changes with mode conversion current drive on Alcator C-Mod , 2007 .