SUMMARY OF 4th IPTA TRANSPORT AND ITB PHYSICS TG MEETING St. Petersburg, Russia, April 8-11, 2003 Presented by E.J. Doyle for the TG Note: this summary does not cover the joint sessions with the CDBM TG, or the discussions on the generation of the Tokamak Physics Basis Document

TPB Structure St.. Petersburg INTERNATIONAL COLLABORATIVE EXPERIMENTS JET, very extensive response to ITPA requests —US participation, JA uncertain DIII-D, more limited response, concentrated on hybrid and steady-sate scenarios, as well as QDB/QH-mode —EU is participating JT-60U, experimental planning is not complete, participation will depend on exact dates and experiments run AUG - not represented at this meeting, need details TEXTOR - new capabilities will be employed in 2003, intention is to contribute to no-momentum ITB studies Conclusion: process will need time to settle down, but good start —Key for future will be ability to participate in experimental planning stage —Need better experimental definitions in future —Action item, to pursue turbulence simulations for T-10 data set, initial contacts made with J. Weiland

TPB Structure St.. Petersburg INTERNATIONAL PROFILE DATABASE STATUS Database manager, T. Fukuda, has resigned —Replacement to be discussed at ITBDB working meeting Discusses scalar ITB database, desirability of incorporating into common ITPA format —Agreed that this is desirable, practical questions to be pursued with K. Thomsen Reviewed status of data entry, incompatibilities between versions, etc. —Further data selection to be made at ITBDB working session Action item: address confusion in community from differing use/meaning of term “profile database” Additional JET data submitted, including pure electron ITB case

TPB Structure St.. Petersburg ITB MODELING Modeling is sensitive to plasma parameters, consequently, choices of how many transport channels to simulate leads to very different final results —Specific example is modeling of same JET discharge using JETTO, but with different no. of channels modeled, results are different  NOTE - This is also true in experiment, tiny changes in conditions have major impact Start made on modeling of edge-core interactions using JET data and JETTO Renormalized version of GLF23 is now available. Fixes problem with calculation of growth rates with negative shear, high alpha. —Action item: test on ITBDB

TPB Structure St.. Petersburg GROUP ACTIVITIES AND PLANS Reviews back on ITB review paper. Many detailed suggestions, but overall quite positive, clear that paper will be published Next meeting in San Diego, after H-mode/ITB Physics workshop, starting Monday September 29 Spring 2004 meeting at JAERI Naka, either week of March 22, or May 10 Response to Diagnostic TG: making progress on detailed response to diagnostic justifications. Start made on modeling of effect of diagnostic resolution using transport codes

TPB Structure St.. Petersburg UPDATE ON RECENT RESULTS Extensive set of experiments performed on JET since 2002 IAEA. Highlights include: —JET/AUG experiment to replicate improved H-mode regime was successful —However, attempt to expand improved H-mode regime to higher field, lower rho_star failed —Wide ITBs have been maintained in steady-state plasmas with mild ELM activity and no impurity accumulation —Developed steady-state ITB at high triangularity Several presentations on the role of q profile on ITB formation, on T-10, JT-60U and TUMAN-3M. These effects are not fully understood at present, and are not included in models —Possible overlap in physics with stellarator community, input expected ST research has progressed to the point where NSTX and MAST can start to contribute to work of the group, as well as significant data —Extend turbulence and transport into new regimes, e.g. beta

TPB Structure St.. Petersburg PAPER AND PRESENTATION PLANS Contributed EPS paper and poster by T. Fujita on examination of key parameters for ITB formation has been accepted —Focus of paper will be on testing the applicability of the JET ITB criterion in rho_star —Paper will also discuss physics content of JET criterion, and when it would be expected to be inapplicable —Needs further transport analysis to reach definite conclusion, but much work already done Proposal by X. Litaudon for a paper at H-mode and ITB Physics workshop on Advanced Tokamak Regimes, including a discussion of prospects based on a multi-machine comparison —Intention is to demonstrate that AT regimes are now approaching a level of performance and reliability such that confidence in applicability to ITER operation is substantially enhanced —Use of multi-machine data is key to conveying readiness