Author: L. C. JohnsonPublisher:
ISBN:
Category : Alpha rays
Languages : en
Pages : 36
Book Description
ICRF Heating of TFTR Deuterium Supershot Plasmas in the 3He Minority Regime
Author: L. C. JohnsonPublisher:
ISBN:
Category : Alpha rays
Languages : en
Pages : 36
Book Description
ICRF Heating of TFTR Deuterium Supershot Plasmas in the 3He Minority Regime
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 36
Book Description
The increased core electron temperature produced by ICRF heating of TFTR, D-T neutral-beam-heated supershot plasmas is expected to extend the alpha particle slowing down time and hence enhance the central alpha particle pressure. In preparation for the TFTR D-T operational phase, which is due to start in late 1993, a series of experiments were conducted on TFTR to explore the effect of ICRF heating on the performance and stability of low recycling, deuterium supershot plasmas in the 3He minority heating regime. The coupling of up to 7.4 MW of 47 MHz ICRF power to full size, 3He minority, deuterium supershots heated with up to 30 MW of deuterium neutral beam injection has resulted in a significant increase in core electron temperature. Simulations of equivalent D-T supershots predict that such ICRF heating should result in approximately a 60% increase in the alpha particle slowing down time and an enhancement of about 30% in the central alpha pressure. Future experiments to be conducted at ICRF powers up to 12.5 MW during the upcoming TFTR D-T campaign may result in even greater enhancements in core alpha parameters. This paper presents results from experiments performed at an axial toroidal magnetic field of (approximately)4.8T, where the minority resonance was within 0.1--0.15 m of the plasma core. Combined ICRF and neutral beam heating powers in these experiments reached TFTR record levels of over 37 MW, which allowed an exploration of the power loading limits on the carbon limiter tiles. The plasma current was operated at 1.85 and 2.2 MA and sawtooth suppression was observed at the higher plasma current.
ICRF HEATING OF TFTR DEUTERIUM SUPERSHOT PLASMAS IN THE SUP(3)HE MINORITYREGIME.
Author: G. TaylorICRF Heating and Transport of Deuterium-tritium Plasmas in TFTR.
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Book Description
This paper describes results of the first experiments utilizing high-power ion cyclotron range of frequency (ICRF) to heat deuterium-tritium (D-T) plasmas in reactor-relevant regimes on the Tokamak Fusion Test Reactor (TFTR). Results from these experiments have demonstrated efficient core, second harmonic, tritium beating of D-T supershot plasmas with tritium concentrations ranging from 6%-40%. Significant direct ion heating on the order of 60% of the input radio frequency (rf) power has been observed. The measured deposition profiles are in good agreement with two-dimensional modeling code predictions. Energy confinement in an rf-heated supershot is at least similar to that without rf, and possibly better in the electron channel. Efficient electron heating via mode conversion of fast waves to ion Bernstein waves (IBW) has been demonstrated in ohmic, deuterium-deuterium and DT-neutral beam injection plasmas with high concentrations of minority 3He (n{sub 3He}/n{sub e} = 15% - 30%). By changing the 3He concentration or the toroidal field strength, the location of the mode-conversion radius was varied. The power deposition profile measured with rf power modulation indicated that up to 70% of the power can be deposited on electrons at an off-axis position. Preliminary results with up to 4 MW coupled into the plasma by 90-degree phased antennas showed directional propagation of the mode-converted IBW. Analysis of heat wave propagation showed no strong inward thermal pinch in off-axis heating of an ohmically-heated target plasma in TFTR.
Energy Research Abstracts
Author: ICRF Heating of Deuterium-tritium Plasmas in TFTR.
Author: H. G. AdlerPublisher:
ISBN:
Category : Tokamak Fusion Test Reactor (Project).
Languages : en
Pages : 13
Book Description
ICRF Heating of Deuterium-tritium Plasmas in TFTR.
Author: H. G. AdlerPublisher:
ISBN:
Category : Tokamak Fusion Test Reactor (Project)
Languages : en
Pages : 13
Book Description
Ch'ugwan chi chung
Author: Modeling of High Power ICRF Heating Experiments on TFTR.
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 4
Book Description
Over the past two years, ICRF heating experiments have been performed on TFTR in the hydrogen minority heating regime with power levels reaching 11.2 MW in helium-4 majority plasmas and 8.4 MW in deuterium majority plasmas. For these power levels, the minority hydrogen ions, which comprise typically less than 10% of the total electron density, evolve into la very energetic, anisotropic non-Maxwellian distribution. Indeed, the excess perpendicular stored energy in these plasmas associated with the energetic minority tail ions is often as high as 25% of the total stored energy, as inferred from magnetic measurements. Enhanced losses of 0.5 MeV protons consistent with the presence of an energetic hydrogen component have also been observed. In ICRF heating experiments on JET at comparable and higher power levels and with similar parameters, it has been suggested that finite banana width effects have a noticeable effect on the ICRF power deposition. In particular, models indicate that finite orbit width effects lead to a reduction in the total stored energy and of the tail energy in the center of the plasma, relative to that predicted by the zero banana width models. In this paper, detailed comparisons between the calculated ICRF power deposition profiles and experimentally measured quantities will be presented which indicate that significant deviations from the zero banana width models occur even for modest power levels (P{sub rf} (approximately) 6 MW) in the TFTR experiments.
DT Simulation of ICRF Heated Supershots in TFTR Using TRANSP.
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 5
Book Description
The principal goal of ion cyclotron range of frequency (ICRF) heating on the Tokamak Fusion Test Reactor (TFTR) is to enhance plasma performance during the deuterium-tritium (DT) physics phase of operations. Strongly centralized ICRF heating may play a critical role in obtaining high Q{sub DT} and high [beta]{sub {alpha}} operation in TFTR, as well as in future fusion reactors. ICRF heating of a dilute minority species leads to the formation of an energetic ion population that, in turn, provides strong central electron heating. The corresponding rise in the central electron temperature translates into an increase in the slowing-down time of either neutral beam or alpha particles in the discharge. Preliminary DT simulations of the experimental results in deuterium-deuterium (DD) plasmas performed with the TRANSP code are presented in this paper.