Fast scanning probe for tokamak plasmas

Boedo, J. A.; Gray, D.S.; Chousal, L.; Conn, R.W.; Hiller, Brigitte; Finken, K.H.

doi:10.1063/1.1148995

Cited by 69 publications

(44 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The latter lead to E θ ×B t and E r ×B t drifts with resultant cross-field and poloidal particle fluxes, respectively [129]. Direct measurements of the private flux region E r ~ 3T e /λ q ~ 5-20 kV/m [54,130,131] suggests that E×B fluxes are comparable to the parallel fluxes under attached conditions, but are substantially smaller following detachment [131]. Enhancement of the divertor parallel flows upon detachment have been both measured [130,6] and simulated using UEDGE and B2 [132,133].…”

Section: Sol Flow and Classical Drifts Effectsmentioning

confidence: 99%

“…Characterized as a 'shoulder', extending from approximately one steep-gradient scale length outside the separatrix to the wall (e.g., ASDEX [43,44], ASDEXUpgrade [45,46], TEXT-U [47], DIII-D [48,49], C-Mod [50,51], JT-60U [52], JET [53], TEXTOR [54], TCV [55]). The earliest hints that cross-field particle transport in the far SOL toward the main-chamber walls could be important for a tokamak reactor, competing with, or even exceeding, the parallel loss into the divertor, came from ASDEX-Upgrade [45,46].…”

Section: Particle Transport In the Solmentioning

confidence: 99%

See 1 more Smart Citation

Chapter 4: Power and particle control

Divertor¹,

Database²,

Editors³

1999

Nucl. Fusion

282

View full text Add to dashboard Cite

Abstract.Progress, since the ITER Physics Basis publication, in understanding the processes that will determine the properties of the plasma edge and its interaction with material elements in ITER is described. Experimental areas where significant progress has taken place are : energy transport in the SOL in particular of the anomalous transport scaling, particle transport in the SOL that plays a major role in the interaction of diverted plasmas with the main chamber material elements, ELM energy deposition on material elements and the transport mechanism for the ELM energy from the main plasma to the plasma facing components, the physics of plasma detachment and neutral dynamics including the edge density profile structure and the control of plasma particle content and He removal, the erosion of low and high Z materials in fusion devices, their transport to the core plasma and their migration at the plasma edge including the formation of mixed materials, the processes determining the size and location of the retention of tritium in fusion devices and methods to remove it and the processes determining the efficiency of the various fuelling methods as well as their development towards the ITER requirements. This experimental progress has been accompanied by the development of modelling tools for the physical processes at the edge plasma and plasma-materials interaction and the further validation of these models by comparing their predictions with the new experimental results. Progress in the modelling development and validation has been mostly concentrated in the following areas : refinement of the predictions for ITER with plasma edge modelling codes by inclusion of detailed geometrical features of the divertor and the introduction of physical effects, which can play a 2 major role in determining the divertor parameters at the divertor for ITER conditions such as hydrogen radiation transport and neutral-neutral collisions, modelling of the ion orbits at the plasma edge, which can play a role in determining power deposition at the divertor target, models for plasma-materials and plasma dynamics interaction during ELMs and disruptions, models for the transport of impurities at the plasma edge to describe the core contamination by impurities and the migration of eroded materials at the edge plasma and its associated tritium retention and models for the turbulent processes that determine the anomalous transport of energy and particles across the SOL. The implications for the expected performance of the reference regimes in ITER, the operation of the ITER device and the lifetime of the plasma facing materials are discussed. Introduction.This chapter outlines the significant progress achieved since the ITER Physics Basis in understanding basic scrape-off layer (SOL) and divertor processes in a tokamak. The interaction of plasma with first-wall surfaces will have considerable impact on the performance of fusion plasmas, the lifetime of plasma facing components, and the retention of tritium in next step Burning Plasma E...

show abstract

Section: Sol Flow and Classical Drifts Effectsmentioning

confidence: 99%

Section: Particle Transport In the Solmentioning

confidence: 99%

Chapter 4: Power and particle control

Divertor¹,

Database²,

Editors³

1999

Nucl. Fusion

282

View full text Add to dashboard Cite

show abstract

“…The balance between parallel and perpendicular transport results in a SOL which is thin compared to its length 1 and the observed SOL profiles are mostly exponential 2 with short ͑1-3 cm͒ decay lengths. However, there is ample [3][4][5] evidence that the SOL profiles are sometimes wider than usual and nonexponential and flat far away from the last closed flux surface ͑LCFS͒, suggesting that perpendicular transport in these conditions can be larger than expected.…”

Section: Introductionmentioning

confidence: 99%

Transport by intermittent convection in the boundary of the DIII-D tokamak

et al. 2001

View full text Add to dashboard Cite

Intermittent plasma objects ͑IPOs͒ featuring higher pressure than the surrounding plasma, and responsible for ϳ50% of the EϫB T radial transport, are observed in the scrape off layer ͑SOL͒ and edge of the DIII-D tokamak ͓J. Watkins et al., Rev. Sci. Instrum. 63, 4728 ͑1992͔͒. Conditional averaging reveals that the IPOs, produced at a rate of ϳ3ϫ10 3 s Ϫ1 , are positively charged and also polarized, featuring poloidal electric fields of up to 4000 V/m. The IPOs move poloidally at speeds of up to 5000 m/s and radially with EϫB T /B 2 velocities of ϳ2600 m/s near the last closed flux surface ͑LCFS͒, and ϳ330 m/s near the wall. The IPOs slow down as they shrink in radial size from 4 cm at the LCFS to 0.5 cm near the wall. The IPOs appear in the SOL of both L and H mode discharges and are responsible for nearly 50% of the SOL radial EϫB transport at all radii; however, they are highly reduced in absolute amplitude in H-mode conditions.

show abstract

“…The balance between parallel and perpendicular transport results in a SOL which is thin compared to its length [1] and the observed SOL density profiles are mostly exponential [2] with short (1-3 cm) decay lengths. However, there is ample [3][4][5] evidence that the SOL density profiles are sometimes wider than usual and non-exponential and flat far away from the last closed flux surface (LCFS), suggesting that perpendicular transport in these conditions can be larger than expected.…”

Section: Introductionmentioning

confidence: 99%

Intermittent convection in the boundary of DIII-D

Boedo

Rudakov

Colchin

et al. 2003

Journal of Nuclear Materials

View full text Add to dashboard Cite

Intermittent plasma objects (IPOs) featuring higher pressure than the surrounding plasma, and responsible for $50% of the E Â B T radial transport, are observed in the scrape-off layer (SOL) and edge of the DIII-D tokamak. The skewness (i.e., asymmetry of fluctuations from the average) of probe and BES intermittent data suggest IPO formation at or near the last closed flux surface (LCFS) and the existence of hole-IPO pairs. The particle content of the IPOs at the LCFS is linearly dependent on the discharge density, however, when normalized to the local averaged density, it is fairly insensitive to density variations. It is also shown that the IPOs thermalize with the background plasma within 1 cm of the LCFS. The IPOs appear in the SOL of both L and H mode discharges carrying $50% of the total SOL radial E Â B T transport at all radii. However, the total flux and the IPO contribution, are highly reduced in H -mode conditions due to the increased confinement.

show abstract

Fast scanning probe for tokamak plasmas

Cited by 69 publications

References 20 publications

Chapter 4: Power and particle control

Chapter 4: Power and particle control

Transport by intermittent convection in the boundary of the DIII-D tokamak

Intermittent convection in the boundary of DIII-D

Contact Info

Product

Resources

About