Nonlocal energetic particle mode in a JT-60U plasma

Journal Article · Sat Jan 01 04:00:00 EST 2005 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.1828084· OSTI ID:20657969

Todo, Y; Shinohara, K; Takechi, M; Ishikawa, M ^[1]

---

1. National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan)

Energetic-ion driven instability in a Japan Atomic Energy Research Institute Tokamak-60 Upgrade (JT-60U) [S. Ishida et al., Phys. Plasmas 11, 2532 (2004)] plasma was investigated using a simulation code for magnetohydrodynamics and energetic particles. The spatial profile of the unstable mode peaks near the plasma center where the safety factor profile is flat. The unstable mode is not a toroidal Alfven eigenmode (TAE) because the spatial profile deviates from the expected location of TAE and the spatial profile consists of a single primary harmonic m/n=2/1 where m and n are poloidal and toroidal mode numbers. The real frequency of the unstable mode is close to the experimental starting frequency of the fast frequency sweeping mode. Simulation results demonstrate that energetic-ion orbit width and energetic-ion pressure significantly broaden radial profile of the unstable mode. For the smallest value among the investigated energetic-ion orbit width, the unstable mode is localized within 20% of the minor radius. This gives an upper limit of the spatial profile width of the unstable mode which the magnetohydrodynamic effects alone can induce. For the experimental condition of the JT-60U plasma, energetic ions broaden the radial width of the unstable mode spatial profile by a factor of 3. The unstable mode is primarily induced by the energetic particles.

• OSTI ID: 20657969
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 1 Vol. 12; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
IONS
JT-60U TOKAMAK
MAGNETOHYDRODYNAMICS
PLASMA
PLASMA INSTABILITY
PLASMA SIMULATION