Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 10
Book Description
Development in DIII-D of High Beta Discharges Appropriate for Steady-state Tokamak Operation With Burning Plasmas
Author: Development of Burning Plasma and Advanced Scenarios in the DIII-D Tokamak
Author: T. C. LucePublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Significant progress in the development of burning plasma scenarios, steady-state scenarios at high fusion performance, and basic tokamak physics has been made by the DIII-D Team. Discharges similar to the ITER baseline scenario have demonstrated normalized fusion performance nearly 50% higher than required for Q = 10 in ITER, under stationary conditions. Discharges that extrapolate to Q {approx} 10 for longer than one hour in ITER at reduced current have also been demonstrated in DIII-D under stationary conditions. Proof of high fusion performance with full noninductive operation has been obtained. Underlying this work are studies validating approaches to confinement extrapolation, disruption avoidance and mitigation, tritium retention, ELM avoidance, and operation above the no-wall pressure limit. In addition, the unique capabilities of the DIII-D facility have advanced studies of the sawtooth instability with unprecedented time and space resolution, threshold behavior in the electron heat transport, and rotation in plasmas in the absence of external torque.
Development of Burning Plasma and Advanced Scenarios in the DIII-D Tokamak
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Significant progress in the development of burning plasma scenarios, steady-state scenarios at high fusion performance, and basic tokamak physics has been made by the DIII-D Team. Discharges similar to the ITER baseline scenario have demonstrated normalized fusion performance nearly 50% higher than required for Q = 10 in ITER, under stationary conditions. Discharges that extrapolate to Q (almost equal to) 10 for longer than one hour in ITER at reduced current have also been demonstrated in DIII-D under stationary conditions. Proof of high fusion performance with full noninductive operation has been obtained. Underlying this work are studies validating approaches to confinement extrapolation, disruption avoidance and mitigation, tritium retention, ELM avoidance, and operation above the no-wall pressure limit. In addition, the unique capabilities of the DIII-D facility have advanced studies of the sawtooth instability with unprecedented time and space resolution, threshold behavior in the electron heat transport, and rotation in plasmas in the absence of external torque.
DEVELOPMENT IN THE DIII-D TOKAMAK OF HYBRID OPERATION SCENARIOS FOR BURNING PLASMA EXPERIMENTS.
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
OAK-B135 The basic parameters of proposed burning plasma experiments such as ITER and FIRE have been chosen based on analysis of multi-machine databases of confinement, stability, and divertor operation. given these specifications, it is of interest to run discharges in present-day machines such as DIII-D to verify the design basis and evaluate the margin available to achieve the mission goals. it is especially important to operate discharges which are stationary with respect to the current relaxation time scale ([tau][sub R]) since it is well-known that higher performance can be achieved transiently. Attention has been focused on validating the baseline scenario for diverted machines--ELMing H-mode discharges with q[sub 95]= 3 with sawteeth. However, there is also interest in the ITER program to assess the feasibility of operating the tokamak in a mode to maximize the neutron fluence for the purpose of testing the design of various components critical to the nuclear fuel cycle and energy conversion systems in a fusion power plant. It was originally envisioned that these discharges would be intermediate between an inductive burn (baseline) scenario and a fully noninductive (steady state) scenario; therefore, this type of discharge has become known as a hybrid scenario. In the course of investigating these hybrid scenarios in DIII-D, two key results have been obtained. First, stationary discharges with q[sub 95]> 4 have been obtained which project to Q[sub fus][approx] 10 in ITER. The projected duration of these discharges in ITER when using the full inductive flux capability is> 4000 s. (The significant engineering issues of site heat capacity, activation, and tritium consumption are beyond the scope of this work). Second, utilizing the same plasma initiation techniques as developed for the hybrid scenario, discharges at q[sub 95]= 3.2 project to near ignition in ITER, even with reduced parameters. This indicates the ITER design has significant performance margin and possesses the physics capability to carry out an extensive nuclear testing program. These same q[sub 95]= 3.2 discharges project to Q[sub fus]> 5 in FIRE, even with pessimistic confinement scalings.
CONTROL OF MHD STABILITY IN DIII-D ADVANCED TOKAMAK DISCHARGES.
Author: M. MURAKAMIКоллективный договор фанерного треста с Ц. к. деревообделочников и Ц. к. химиков
Author: The Franco-American Convention Relative to Double Taxation
Author: Emmet McCafferyProduction and Stability of High-beta DIII-D Discharges with Reversed Magnetic Shear
Author: Demonstration in the DIII-D Tokamak of an Alternate Baseline Scenario for Iter and Other Burning Plasma Experiments
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Book Description
OAK A271 DEMONSTRATION IN THE DIII-D TOKAMAK OF AN ALTERNATE BASELINE SCENARIO FOR ITER AND OTHER BURNING PLASMA EXPERIMENTS. Discharges which can satisfy the high gain goals of burning plasma experiments have been demonstrated in the DIII-D tokamak in stationary conditions with relatively low plasma current (q95> 4). A figure of merit for fusion gain [Beta]{sub N}H9/q952 has been maintained at values corresponding to Q = 10 operation in a burning plasma for> 6 s or 36 [tau]{sub E} and 2 [tau]{sub R}. The key element is the relaxation of the current profile to a stationary state with q{sub min}> 1, which allows stable operation up to the no-wall ideal [beta] limit. These plasmas maintain particle balance by active pumping rather than transient wall conditions. The reduced current lessens significantly the potential for structural damage in the event of a major disruption.
High-beta, Steady-state Hybrid Scenario on DIII-D.
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Here, the potential of the hybrid scenario (first developed as an advanced inductive scenario for high fluence) as a regime for high-beta, steady-state plasmas is demonstrated on the DIII-D tokamak. These experiments show that the beneficial characteristics of hybrids, namely safety factor ≥1 with low central magnetic shear, high stability limits and excellent confinement, are maintained when strong central current drive (electron cyclotron and neutral beam) is applied to increase the calculated non-inductive fraction to ≈100% (≈50% bootstrap current). The best discharges achieve normalized beta of 3.4, IPB98(y,2) confinement factor of 1.4, surface loop voltage of 0.01 V, and nearly equal electron and ion temperatures at low collisionality. A zero-dimensional physics model shows that steady-state hybrid operation with Qfus ~ 5 is feasible in FDF and ITER. The advantage of the hybrid scenario as an Advanced Tokamak regime is that the external current drive can be deposited near the plasma axis where the efficiency is high; additionally, good alignment between the current drive and plasma current profiles is not necessary as the poloidal magnetic flux pumping self-organizes the current density profile in hybrids with an m/n=3/2 tearing mode.