The use of large surface area for particle and power deposition
- Association Euratom-CEA, Centre d`Etude de Cadarache, 13 - Saint-Paul-lez-Durance (France)
- Oak Ridge National Lab., TN (United States)
Since the parallel heat flux passing through the LCFS has increased dramatically with the size of machines one has to cope with very large particle and power fluxes on the limiters. Thus the size of the limiters has been increased by the use of inner bumper limiters. The ``exponential-sine`` model is widely used to estimate the heat flux (Q) to a wall for a plasma flux surface with incident angle {theta}. The model predicts Q= q{sub {parallel}}(O) sin{theta} e{sup {minus}} {sup {rho}}/{lambda}q + q{perpendicular}(O)cos{theta}e{sup {minus}}{rho}/{lambda}q {rho} is the minor radius measured from the last closed flux surface (LCFS), {lambda}{sub q} is the SOL decay length of the heat, flux density and q(O) is the heat flux density at the last closed surface. If we approximate the heat flux as Q= q{parallel} e{sup {minus}{rho}}/{lambda}q sin ({theta} + {alpha}), with {alpha}{equivalent_to}tan{sup {minus}1}[q{perpendicular}(0)/q{parallel}(0)], than {alpha} can be interpreted as an effective ``minimum angle of incidence``. Under conditions where the geometric angle 0 has been made almost grazing the predictions of the simplest model is not adequate to represent the observation made in TORE-SUPRA; a similar result is found in TFTR. Experimental observations of heat and particle deposition on the large area limiter on the inner wall of TORE-SUPRA are presented. These results have been analyzed with a Monte Carlo code describing the diffusion of hydrogenic particles across the LCFS to the limiting objects in the Scrape Off Layer, and by impurity generation calculations using the full ``exponential-sine`` model used as input to an impurity Monte Carlo code.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 10177936
- Report Number(s):
- CONF-930720-19; ON: DE93018458
- Resource Relation:
- Conference: 20. European conference on controlled fusion and plasma physics,Lisbon (Portugal),26-30 Jul 1993; Other Information: PBD: [1993]
- Country of Publication:
- United States
- Language:
- English
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