Characterization of the Pedestal in Alcator C-Mod ELMing H-Modes and Comparison to the EPED Model
نویسندگان
چکیده
A dedicated series of ELMing H-Mode discharges on Alcator C-Mod spanning a broad range of plasma parameters, including plasma current (400-1000kA), magnetic field (3.5-8T), and plasma shaping, are presented with experimental scalings of the plasma pedestal with bulk plasma and engineering parameters. The H-modes presented achieve pedestals with densities spanning 5 × 10 − 2.5 × 10 m−3 and temperatures of 150− 1000 eV (corresponding to 5− 40 kPa in the pressure pedestal), over a width of 3− 5% of poloidal flux. The observed pedestal structure is compared with the most recent iteration of the EPED class of models, which uniquely predict the pedestal width and height for a set of scalar input parameters via a combination of stability calculations for peeling-ballooning MHD modes and kinetic ballooning modes (KBM). PACS numbers: 52.55.Fa,52.55.Tn,52.25.Fi,52.40.Hf,52.35.Py EPED Model on C-Mod 2
منابع مشابه
Predicting the Pedestal : Results and Lessons Learned from Experiments to Test Pre - Experiment EPED Predictions , Including the Super H Regime
Developing a validated predictive capability is critical to the design, optimization and successful operation of fusion experiments. However, in part because of the coupled, multi-physics nature of tokamak plasmas, it can be challenging to isolate physics and control an experiment sufficiently to precisely test predictions. Here we report on experience with planning, execution and analysis of e...
متن کاملEdge profile stiffness and insensitivity of the density pedestal to neutral fueling in Alcator C-Mod edge transport barriers
Mechanisms determining the structure of edge temperature and density pedestals, which are associated with edge transport barrier (ETB) formation in tokamaks, are investigated on Alcator C-Mod. Experiments suggest a strong role for critical gradient behavior in setting profile characteristics of edge plasma. The maximum pressure gradient scales as the square of plasma current in both H-modes wit...
متن کاملPedestal properties of H-modes with negative triangularity using the EPED-CH model
The EPED model has been designed to predict the pedestal height and width from a minimal set of parameters and using the stability of the pedestal region for global MHD peeling-ballooning (P-B) modes as well as local Kinetic Balooning Modes (KBMs). This approach has been validated for type-I ELMy H-modes and Quiescent H-modes (QH) but can also be used for other types of H-modes where it usually...
متن کامل1 Edge dimensionless identity experiment on DIII - D and Alcator
Experiments were carried out to study the similarity of H-mode (High confinement mode) physics on the Alcator C-Mod [1] and DIII-D [2] tokamaks comparing plasmas with matched local edge dimensionless parameters (β, ρ∗, ν∗, q95) and shape (ε, κ, δ). It was observed that matching local values of the dimensionless parameters on top of the H-mode pedestals produces similar Te and ne profiles across...
متن کاملPSFC / JA - 05 - 46 Advances in measurement and modeling of the high - confinement - mode pedestal on the Alcator C - Mod tokamak
Edge transport barrier (ETB) studies on the Alcator C-Mod tokamak [Phys. Plasmas 1, 1511, (1994)] investigate pedestal scalings and radial transport of plasma and neutrals. Pedestal profiles show trends with plasma operational parameters such as total current IP . A ballooning-like I2 P dependence is seen in the pressure gradient, despite calculated stability to ideal ballooning modes. A simila...
متن کامل