D majority heating in JET plasmas: ICRH modelling and experimental RF deposition

Journal Article · Fri Sep 28 04:00:00 EDT 2007 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2800547· OSTI ID:21035922

Lerche, E; Eester, D van; Lamalle, P ^[1]; Krasilnikov, A ^[2]

---

1. Laboratory for Plasma Physics, Association 'EURATOM-Belgian State', Trilateral Euregio Cluster, Royal Military Academy, Brussels (Belgium)
2. SRC RF Troisk Institute for Innovating and Fusion Research, Troisk (Russian Federation)

Recent experiments in JET have provided information on the potential of using majority RF heating schemes in large plasmas. Adopting a wide range of available diagnostics, the plasma behaviour was monitored. The main results of the experiments are that--due to the poor antenna coupling at low frequency, the low (Ohmic) plasma temperature and the reduced RF electric field amplitude near the ion-cyclotron resonance layer of the majority ions--ICRH alone is barely capable of heating the plasma. On the other hand, when preheating the plasma using neutral beam injection, the wave-plasma coupling is noticeably improved and considerable plasma heating, followed by increased neutron yield were observed in several diagnostics. This effect is not only attributed to the lower collisionality of the pre-heated plasma but also to the Doppler-shifted IC absorption of the fast beam ions. By studying the response of the plasma to sudden changes in the RF power level, the experimental power deposition profiles were determined and compared to theoretical predictions. The numerical modelling was done adopting a coupled wave/Fokker-Planck code that enables accounting for the non-Maxwellian distributions of the RF heated particles and the injected beam ions in the wave equation, and for the actual local RF fields in the Fokker-Planck description. The theoretical results confirm the experimental finding that the beam ions do play a crucial role in this heating scheme.

• OSTI ID: 21035922
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 933; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANTENNAS
COMPUTERIZED SIMULATION
COUPLING
DIELECTRIC PROPERTIES
ELECTRIC FIELDS
ELECTRON TEMPERATURE
ENERGY ABSORPTION
FOKKER-PLANCK EQUATION
ICR HEATING
ION CYCLOTRON-RESONANCE
ION TEMPERATURE
IONS
JET TOKAMAK
NEUTRAL ATOM BEAM INJECTION
NEUTRONS
PLASMA
PLASMA JETS
PLASMA SIMULATION
RF SYSTEMS
WAVE EQUATIONS