Particles In Magnetic Confinement Systems Research Articles

Editorial: 16th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems—Theory of Plasma Instabilities

Editorial: 16th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems—Theory of Plasma Instabilities

Summary of the 16th IAEA technical meeting on energetic particles in magnetic confinement systems—theory of plasma instabilities

This report summarizes the contributions presented at the 16th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems—Theory of Plasma Instabilities, held in Shizuoka, Japan, 3–6 September 2019. The meeting brought together about 100 experts from nuclear fusion research sites worldwide to discuss the physics of energetic particles and plasma instabilities, at the first joint meeting from the two scientific disciplines. The main topics of the meeting were: alpha particles physics; transport of energetic particles; effects of energetic particles in magnetic confinement fusion devices; collective phenomena such as Alfvén eigenmodes, energetic particle modes and others; runaway electrons and disruptions; diagnostics for energetic particles; control of energetic particles confinement; multiscale physics and instabilities in burning plasmas.

Plasma isotopic effect on the damping rate of toroidal Alfvén eigenmodes with intermediate toroidal mode numbers**This paper follows up the contribution presented at the 12th IAEA Technical Committee Meeting on Energetic Particles in Magnetic Confinement Systems (Austin, TX, 8–10 September 2011).

This paper reports on the results of recent experiments performed on the JET tokamak on toroidal Alfvén eigenmodes (TAEs) with toroidal mode number (n) in the range up to |n| = 7. The stability properties of these medium-n TAEs are investigated experimentally using a set of compact in-vessel antennas, providing a direct and real-time measurement of the frequency, damping rate and amplitude for each individual toroidal mode number. The measurements, reported here, of the damping rate (γ/ω) for these medium-n modes were obtained during a deuterium to helium to hydrogen changeover experimental campaign, and are used to infer the effect of the plasma effective isotopic composition (AEFF) on the stability properties of these medium-n TAEs. We find that the damping rate of n = 1 TAEs decreases approximately as γ/ω ∼ 1/AEFF as reported previously, but only for modes whose frequency is close to the centre of the n = 1 toroidal gap and for density and current profiles giving an open gap structure. Conversely, for n ⩾ 3 TAEs we find that their damping rate approximately increases as γ/ω ∼ AEFF.

Features of ion and electron fishbone instabilities on HL-2A**The 11th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems, 21–23 September 2009, Kyiv, Ukraine, OT16.

The features of ion and electron fishbone instabilities have been investigated during neutral beam injection (NBI) and electron cyclotron resonance heating (ECRH) on HL-2A. Some new phenomena, such as frequency jumps and V-font-style sweeping, have been presented in the paper. Three kinds of i-fishbones, including hybrid sawtooth–fishbone (sawbone), run-on fishbone and classical fishbone, have been identified during NBI. During high power (PECRH > 0.7 MW) ECRH, the experimental results indicate that the e-fishbone frequencies are higher than those during low power ECRH, and are provided with up- and down-chirping behaviours, and sometimes also with V-font-style sweeping. The periodic mode frequency jumps have also been detected by a soft x-ray array. It is possible to correlate these phenomena with the redistribution of energetic electrons.

Summary of the 9th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (Takayama, Japan, 9–11 November 2005)

Summary of the 9th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (Takayama, Japan, 9–11 November 2005)

Fast ion absorption of the high harmonic fast wave in the National Spherical Torus Experiment

Ion absorption of the high harmonic fast wave in a spherical torus [Y.-K. M. Peng et al., Nucl. Fusion 26, 769 (1986)] is of critical importance to assessing the viability of the wave as a means of heating and driving current. Analysis of recent National Spherical Torus Experiment [M. Ono et al., Nucl. Fusion 40, 557 (2000)] shots has revealed that under some conditions when neutral beam and rf power are injected into the plasma simultaneously, a fast ion population with energy above the beam injection energy is sustained by the wave. In agreement with modeling, these experiments find the rf-induced fast ion tail strength and neutron rate at lower B-fields to be less enhanced, likely due to a larger β profile, which promotes greater off-axis absorption where the fast ion population is small. Ion loss codes find the increased loss fraction with decreased B insufficient to account for the changes in tail strength, providing further evidence that this is a rf interaction effect. Though greater ion absorption is predicted with lower k∥, surprisingly little variation in the tail was observed, along with a neutron rate enhancement with higher k∥. Data from the neutral particle analyzer, neutron detectors, x-ray crystal spectrometer, and Thomson scattering are presented, along with results from the TRANSP [R. J. Hawryluk, Physics of Plasmas Close to Thermonuclear Conditions 1, 19 (1981); J. P. H. E. Ongena et al., Fusion Technol. 33, 181 (1998)] transport analysis code, ray-tracing codes HPRT [J. Menard et al., Phys. Plasmas 6, 2002 (1999)], and CURRAY [T. K. Mau et al., RF Power in Plasmas: 13th Topical Conference (1999), p. 148], full-wave code AORSA [E. F. Jaeger et al., RF Power in Plasmas: 14th Topical Conference, 2001, p. 369], quasilinear code CQL3D [R. W. Harvey et al., in Proceedings of the IAEA TCM on Advances in Simulation and Modeling of Thermonuclear Plasmas, 1992], and ion loss codes EIGOL [D. S. Darrow et al., in Proceedings of the 6th IAEA TCM on Energetic Particles in Magnetic Confinement Systems, 2000, p. 109] and CONBEAM [J. Egedal et al., Phys. Plasmas 10, 2372 (2003)].

Conference Summary: Energetic particles in magnetic confinement systems

Report on the 7th IAEA Technical Committee Meeting held at the Scandic Hotel Opalen, Gothenburg, Sweden, 8-11 October 2001

Energetic particles in magnetic confinement systems

Report on the 6th IAEA Technical Committee Meeting held at Naka-machi, Naka-gun, Ibaraki, Japan 12-14 October 1999