A. J. Webster
It was shown in the first part to this paper how a simple magnetohydrodynamic model can be used to determine the stability of a tokamak plasma’s edge to peeling external kink modes. It was found that stability is determined by the value of , a normalized measure of the discontinuity in the radial derivative of the radial perturbation to the magne…
PublishedJ. P. Graves I. Chapman S. Coda L.-G. Eriksson T. Johnson
The sawtooth control mechanism in plasmas employing off-axis toroidally propagating ion cyclotron resonance waves in tokamaks is reinvestigated. The radial drift excursion of energetic passing ions distributed asymmetrically in the velocity parallel to the magnetic field determines stability when the rational q 1/4 1 surface resides within a narrow…
PublishedP. Jacquet G. Bergerby V. Bobkov T. Blackman F. Durodié et al.
A Sub-Harmonic Arc Detection (SHAD) system has been installed on the transmission lines feeding the JET ICRF ITER-like-Antenna (ILA). Along with the commissioning of SHAD, extensive measurements of the RF field in the transmission lines were carried-out using fast sampling (125 Mb/s) oscilloscopes. The system is described, and the SHAD ability to d…
PublishedT. Tokuzawa K. Kawahata Y. Nagayama S. Inagaki P. C. De Vries A. Mase Y. Kogi Y. Yokota H. Hojo K. Tanaka A. Ejiri R. O. Pavlichenko S. Yamaguchi T. Yoshinaga D. Kuwahara Z. Shi H. Tsuchiya Y. Ito S. Hirokura S. Sudo A. Komori Lhd
Several types of microwave diagnostics, in the category of electron cyclotron emission (ECE) spectroscopy and reflectometry, have been developed on the Large Helical Device (LHD). Since LHD has a complicated magnetic configuration, the polarization effects have been studied for optimization of the microwave passive and active diagnostics. It was fo…
PublishedPui-Wai Ma C. H. Woo S. L. Dudarev
Finite temperature magnetic properties of iron thin films are investigated, up to ferro/paramagnetic transition. The coupled dynamics of atoms and magnetic moments is treated using large-scale spin-lattice dynamics (SLD) simulations. A comprehensive study of surface and bulk magnetic properties is conducted, to investigate their dependences on temp…
PublishedA. Thyagaraja K. G. McClements
Equations describing the nonrelativistic motion of a charged particle in an arbitrary noninertial reference frame are derived from the relativistically invariant form of the particle action. It is shown that the equations of motion can be written in the same form in inertial and noninertial frames, with the effective electric and magnetic fields in…
PublishedM. K. Lilley B. N. Breizman S. E. Sharapov
The nonlinear evolution of waves excited by the resonant interaction with energetic particles, just above the instability threshold, is shown to depend on the type of relaxation process that restores the unstable distribution function. When dynamical friction dominates over diffusion in the phase space region surrounding the wave-particle resonance…
PublishedP. U. Lamalle B. Beaumont T. Gassmann F. Kazarian B. Arambhadiya et al.
The ITER Ion Cyclotron Heating and Current Drive system will deliver 20MW of radio frequency power to the plasma in quasi continuous operation during the different phases of the experimental programme. The system also has to perform conditioning of the tokamak first wall at low power between main plasma discharges. This broad range of reqiurements …
PublishedColin Windsor Geoff Cottrell Richard Kemp
Recent predictions have been made of metallurgical properties of low-activation ferritic/martensitic steels alloys at the high irradiation levels (displacements per atom or dpa) needed for a fusion power plant as based on measurements at low irradiation levels where more data is available. These have been published for the yield stress and for the …
PublishedS. Chiesa P. M. Derlet S. L. Dudarev
The stability of interstitial defect and dislocation structures in bcc Fe as a function of temperature is believed to play a crucial role in determining defect evolution under irradiation conditions. The vibrational properties of defects constitute one contribution to the corresponding energetics and much work has been done within the harmonic appr…
Published