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ELM mitigation with SMBI-CJI fuelling in HL-2A H-mode plasmas. C. Y. Chen, L. H. Yao, B.B. Feng, Z. B. Shi, W.L. Zhong, J. Cheng, D. L. Yu, X. R. Duan Southwestern Institute of Physic 2012/05/17. SMBI & CJI Fuelling deposition area ELM mitigation ELM mitigation with SMBI
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ELM mitigation with SMBI-CJI fuelling in HL-2A H-mode plasmas C. Y. Chen, L. H. Yao, B.B. Feng, Z. B. Shi, W.L. Zhong, J. Cheng, D. L. Yu, X. R. Duan Southwestern Institute of Physic 2012/05/17
SMBI & CJI Fuelling deposition area ELM mitigation ELM mitigation with SMBI ELM mitigation with CJI Summary and discussion Outline
A Solid / liquid (P ,T ) 0 0 log P isentrope B C P (T) v gas P(T) log T SMBI & CJI The gas state changes follow the isentrope, over the saturated vapor pressure line, molecular combined together to clusters in the beam. The gas expands adiabatically, the flow velocity increases and Mach number continues to increases to M>>1 in the zone of silence.
SMBI & CJI Rayleigh scattering and electron fluorescence method to measure the clusters.
SMBI & CJI Pressure: 1.65MPa Pulse duration: 2 ms Temprature: -156℃ Delay time: ~1 ms ~1ms Pressure: 1.45 MPa Pulse duration: 2 ms Room temprature Delay time: ~ 0.8 ms ~0.8ms
Deposition area of SMBI SMBI parameters for shot 14045 (H-mode) :P = 1.2 MPa, pulse duration 3 ms, separatrix on r = 37 cm, D particles deposited area around r = 36.5 cm。
Deposition area of CJI • CJI could send particles to the pedestal top.
ELM mitigation a b c Bt: 1.4 T IP: 150 ~ 180 kA Ne: 1.4 ~ 2.4 ECRH:1 ~ 1.5 MW NBI: 0.5 ~ 0.8 MW ELMs mitigation with SMBI (a),CJI (b),He SMBI (c).
ELM mitigation with SMBI ~ 2-3.5 are achieved. • Significant change of the ELM signal after SMBI pulse. • The influence persistence time last longer as the injected particles increasing.
ELM mitigation with CJI Multi - CJI Pressure: 1.4 MPa Duration: 2 ms Power: 1 MW NBI
ELM mitigation Pressure: 1.1 MPa Duration: 4 ms Room temperature Pressure: 4 MPa Duration: 0.6 ms Temperature: - 156 ℃ The comparison of SMBI and CJI on ELM mitigation
ELM mitigation • The heat flux at divertor plate remains the same approximately, the filaments number (2.5) increases by 30%. • Per-ELM filament carried heart flux at the strike-point decreased 27%, 38%, 57%.
ELM mitigation • Auto-power spectrum of the particle flux measured by Langmuir probe located near the separatrix indicating that the large scale turbulence structures are significantly suppressed, CJI can trigger more small structures (ELM filament or avalanches).
CJI could inject deeper and may fuel to the pedestal top in HL-2A. Experiment results show that SMBI & CJI fuelling are able to mitigate ELM on HL-2A. CJI fuelling has the potential to control ELM on larger fusion device. Larger cluster deeper injection? CJI benefit from deeper injection for ELM mitigation? CJI fuelling have the potential to control ELM on larger fusion devices? Summary and discussion