SOL width in limited versus diverted discharges in DIII-D

• Published in: Journal of nuclear materials Vol. 415; no. 1; pp. S387 - S390
• Main Authors: Rudakov, D.L., Boedo, J.A., Pitts, R.A., Jackson, G.L., Lasnier, C.J., Leonard, A.W., Moyer, R.A., Stangeby, P.C., Tynan, G.R., Watkins, J.G.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-08-2011; Elsevier
• Subjects: Applied sciences; Benchmarking; Controled nuclear fusion plants; Correlation; Density; Elongation; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Flux; Fuels; Installations for energy generation and conversion: thermal and electrical energy; Langmuir-Blodgett films; Nuclear fuels; Nuclear power generation; Uncertainty; Tokamak; Nuclear fusion reactor; Scrape-off layer; Nuclear reactor
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2010.10.036

An experiment aimed at benchmarking the ITER scrape-off layer (SOL) power width scaling in limited L-mode discharges has been conducted on DIII-D. Scans of the main scaling parameters were performed in an inner-wall-limited (IWL) magnetic configuration. Using the near-SOL density and temperature e-folding lengths, λn, λT, determined from reciprocating Langmuir probe measurements, SOL power flux density e-folding lengths, λq, are derived. A few lower single null (LSN) discharges were also run for comparison. The results are generally in agreement with the ITER design assumptions, finding that λn and λT are correlated (λT∼1.2λn) and both λn and λT are on average 2.1–2.5 times larger in IWL configurations than in LSN. In moderate elongation (κ∼1.4) IWL discharges, λq is largest and agrees with the assumed ITER scaling within the estimated uncertainty (a factor of ∼2). In IWL discharges λq measurements are consistent with the expectations of SOL power balance.