Assessment of critical physical assumptions in consistent 2D plasma edge modelling

Baelmans, Martine; Reiter, D.; Kever, H.; Börner, P.; Wuttke, M. W.; Pütz, Th.; Schneider, R.; Maddison, G.; Braams, Bastiaan J.; Weynants, R.R.

doi:10.1016/s0022-3115(06)80080-2

Cited by 11 publications

(3 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At the radially-extended limiter surfaces, sheath BC's are applied. 15 At the inner and outer boundaries, T e , T i , and n are each set to a constant value over the flux surface; the values at the inner boundary are chosen as described in the Appendix, and those at the outer boundary are chosen for profile smoothness. At the inner boundary, v ʈ is set to zero, and at the outer boundary, the radial flux of the parallel momentum is prescribed to be zero.…”

Section: Transport Coefficients and Boundary Conditionsmentioning

confidence: 99%

Self-consistent plasma-neutral modeling in tokamak plasmas with a large-area toroidal belt limiter

et al. 1999

Self Cite

View full text Add to dashboard Cite

Plasma-neutral phenomena in the edge plasma and scrape-off layer of the Torus Experiment for Technology Oriented Research [G.H. Wolf and the TEXTOR Team, J. Nucl. Mater. 122&123, 1124 (1984)] with the toroidal belt Advanced Limiter Test (ALT-II) [D.M. Goebel et al., J. Nucl. Mater. 162–164, 115 (1989)] are simulated using the code package B2-EIRENE [D. Reiter et al., Plasma Phys. Controlled Fusion 33, 1579 (1991)]. Spatially-constant, anomalous radial transport coefficients (D,V,χ) are used for fitting measured electron temperature and density profiles. Primary neutral fluxes are determined by plasma fluxes to material surfaces, and Dα emissions are predicted from them. Comparison of the predicted Dα emission with measurements indicates a critical need, in predictive modeling, for a self-consistent model of fluxes to material surfaces that are parallel to the magnetic field. Appropriate factors are calculated for deducing D+ source rates from Dα emissions measured in various locations, taking into account molecular processes and spatially varying plasma parameters; values range from 17 to 28 ions/photon. Ion fluxes lost to pumps or the wall must be explicitly re-introduced as neutral fluxes at the outer boundary.

show abstract

Section: Transport Coefficients and Boundary Conditionsmentioning

confidence: 99%

Self-consistent plasma-neutral modeling in tokamak plasmas with a large-area toroidal belt limiter

et al. 1999

Self Cite

View full text Add to dashboard Cite

show abstract

“…Two dimensional plasma-neutral modelling of the boundary region has been carried out in order to help interpret D + source rates from Dα measurements, to compare experimental results with the predictions of a commonly used computer model and to check the internal consistency of various measurements. The code used for this purpose is the B2-EIRENE package [47,48], which iterates between the fluid plasma code B2 and the Monte Carlo neutral transport code EIRENE, each of the two providing necessary inputs for the other (these inputs being the plasma background for EIRENE and the source terms for the fluid equations in B2). This modelling work is described in greater detail in a separate article [49].…”

Section: Plasma-neutral Modelling Of the Textor Boundarymentioning

confidence: 99%

Plasma exhaust and density control in tokamak fusion experiments with neutral beam or ICRF auxiliary heating

et al. 1998

View full text Add to dashboard Cite

Particle exhaust studies have been carried out with the pump limiter ALT-II in the TEXTOR tokamak, under ohmic conditions as well as with NBI and with ICRF auxiliary heating, and the pumping effectiveness is shown to meet the requirements for a fusion reactor. Quantitative measurements of Dα emission, made with a CCD camera, have been used to determine the particle efflux from the plasma. Roughly one third of the Dα emission occurs in a diffuse `halo' that surrounds the limiter belt. The particle confinement time is less than the energy confinement time by a factor of typically 4. Modelling in 2-D of plasma and neutral flows in the TEXTOR boundary has been performed. The source of D+ ions can be related to the Dα emission by a factor that is found to depend on the location of the emission and on the discharge density. The predicted total Dα emission agrees with the measurements within a factor of about 2. Pumping of ALT-II allows for density control; with NBI, the density can be increased well beyond the ohmic limit without the discharge ending in disruption. The plasma particle efflux and the pumped flux both increase with density as well as with heating power. The exhaust efficiency is typically ∼2%, with the highest values observed in high density NBI discharges. Higher exhaust rates are observed with NBI than with ICRF. Plasma and neutral flows in the ALT-II scoops have been simulated, making use of a simple plasma model. The scoop may be viewed as a non-linear amplifier of the plasma particle flux; the amplification is found to range from about 2 to 3 for most cases. Flow reversal in the scoop is found in some of the NBI cases and particularly in the highest density case.

show abstract

“…3 Understanding the tokamak boundary has profound implications for large fusion projects such as the International Thermonuclear Experimental Reactor ͑ITER͒ and future fusion devices since their performance is limited by the heat load on the plasma facing wall. The future fusion needs are therefore driving an effort in plasma modeling, 4,5 which requires a large database for validation and scaling purposes.…”

Section: Introductionmentioning

confidence: 99%

Fast scanning probe for tokamak plasmas

Boedo

Gray

Chousal

et al. 1998

Review of Scientific Instruments

View full text Add to dashboard Cite

We describe a fast reciprocating probe drive, which has three main new features: ͑1͒ a detachable and modular probe head for easy maintenance, ͑2͒ a combination of high heat flux capability, high bandwidth, and low-Z materials construction, and ͑3͒ low weight, compact, inexpensive construction. The probe is mounted in a fast pneumatic drive in order to reach plasma regions of interest and remain inserted long enough to obtain good statistics while minimizing the heat flux to the tips and head. The drive is pneumatic and has been designed to be compact and reliable to comply with space and maintenance requirements of tokamaks. The probe described here has five tips which obtain a full spectrum of plasma parameters: electron temperature profile T e (r), electron density profile n e (r), floating potential profile V f (r), poloidal electric field profile E (r), saturation current profile I sat (r), and their fluctuations up to 3 MHz. We describe the probe show radial profiles of various parameters. We compare the density and temperature data to that obtained with a helium beam. We also discuss the techniques to process the data optimally, particularly double probe data and profile fits.

show abstract

Assessment of critical physical assumptions in consistent 2D plasma edge modelling

Cited by 11 publications

References 2 publications

Self-consistent plasma-neutral modeling in tokamak plasmas with a large-area toroidal belt limiter

Self-consistent plasma-neutral modeling in tokamak plasmas with a large-area toroidal belt limiter

Plasma exhaust and density control in tokamak fusion experiments with neutral beam or ICRF auxiliary heating

Fast scanning probe for tokamak plasmas

Contact Info

Product

Resources

About