Core and Edge Aspects of Quiescent Double Barrier Operation on Diii-d.with Relevance to Critical Itb Physics Issues
Year: 2003
Type: article
Abstract: OAK-B135 Recent results from DIII-D address critical internal transport barrier (ITB) research issues relating to sustainability, impurity accumulation and ITB control, and have also demonstrated successful application of general profile control tools. In addition, substantial progress has been made in understanding the physics of the Quiescent Double Barrier (QDB) regime, increasing the demonstrating operating space for the regime and improving performance. Highlights include: (1) a clear demonstration of q-profile modification using electron cyclotron current drive (ECCD); (2) successful use of localized profile control using electron cyclotron heating (ECH) or ECCD to reduce central high-Z impurity accumulation associated with density peaking; (3) theory-based modeling codes are now being used to design experiments; (4) the operating space for Quiescent H-mode (QH-mode) has been substantially broadened, in particular higher density operation has been achieved; (5) absolute ({beta} 3.8%, neutron rate S{sub n} {le} 5.5 x 10{sup 15} s{sup -1}) and relative ({beta}{sub N}H{sub 89} = 7 for 10 {tau}{sub E}) performance has been increased; (6) with regard to sustainment, QDB plasmas have been run for 3.8 s or 26 {tau}{sub E}. These results emphasize that it is possible to produce sustained high quality H-mode performance with an edge localized mode (ELM)-free edge, directly addressing a major issue in fusion research, of how to ameliorate or eliminate ELM induced pulsed divertor particle and heat loads.
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W8616197