Workshop Working Groups and Topics
This year, the TTF Workshop will consist of:
i.) (New!) Special Plenary Topical Contributed Sessions
ii.) Working Group Sessions
iii.) Posters
Special Plenary Topical Contributed Sessions
This year we plan to hold two special interdisciplinary plenary contributed sessions. The topics of these sessions are:
SP-1) Transport and Turbulence Near Marginality
This topic encompasses all aspects of the dynamics of turbulence and transport near marginality and/or criticality, in any or all parts of the plasma. Discussion of the relation of this theme to any aspect of transport and/or turbulence dynamics is of interest to TTF and is welcome.
SP-2) Edge-Core Interactions
This topic deals with any and all aspects of the interaction between the core and edge plasma dynamics, including (but not limited to) its effect on all transport channels, L-H transition, intrinsic rotation, ELMs, density limit, etc. Papers submitted for this session should encompass some aspect of both the core and edge, as well as their interaction.
The purpose of these sessions is to stimulate interdisciplinary discussion and interchange on themes common to the TTF as a whole, without the interference of parallel sessions. To this end, these sessions will be PLENARY. Loosely following the style of the EU-US TTF meetings, the plenary sessions will consist of brief introductory overviews, several contributed oral papers, and group discussion, with a discussion leader.
TTF meeting participants are encouraged to submit contributed papers to these two special sessions. The scope of the topics is intentionally broad, so as to accommodate a diversity of approaches. The two topics span all aspects of the TTF. Hence, novel interpretations and directions are very welcome! In the event that a submission to one of the special sessions is not selected, it can be considered for a regular working group.
Working Groups
Each working group includes both theory and experiment, with the ultimate goal being tests of theory, simulations and models against experiment. In addition, diagnostic needs and novel diagnostic ideas for a given area are also included in the scope of each working group. The reality of the ITER project provides extra impetus for work on burning plasma transport issues relevant to each of the working groups.
A. Core Transport Working Group
(D. Newman, G. McKee)
The core working group covers transport issues from the center of the plasma to the top of the H-mode edge pedestal. Topics include:
• Electron and ion thermal transport
• Particle transport
• Momentum transport and generation of rotation
• Profile/transport control/modification issues (e.g. role of rotation, sources, plasma shape, etc.
• Formation, control and dynamics of Internal Transport Barriers
• Core-edge interface (the edge as a dynamic boundary for the core)
• Physics of transport structures (e.g. zonal flows, streamers, avalanches)
• High performance and burning plasmas (i.e. steady state, bootstrap dominated, etc.)
Note: This year the Core and Momentum groups will hold a joint session on the relation between particle and momentum transport, especially the physics of the density and toroidal velocity pinches.
B. Edge Physics Working Group
(R. Groebner, R. Moyer, C.S. Chang)
The Edge Physics group covers transport physics in the region just inside and outside the last closed flux surface, with emphasis on H-mode plasmas. Topics of interest include:
• Physics of H-mode pedestal structure
• Pedestal Transport, sources and sinks
• Transport induced by ELMs and other edge MHD activity
• Transport in the scrape-off layer
• Mechanism for L-H transition, including transient regimes
• Physics of hysteresis and the back-transition
• Physics of the density limit
C. Fast Particle Working Group
(B. Breizman, N.N. Gorelenkov, W. Heidbrink)
• Study of fast-particle-drive instabilities
• Assessment of fast particle effects on burning plasmas performance (e.g. ITER)
• Fast particle diagnostics in burning plasmas
• MHD spectroscopy
• Theory and simulation of nonlinear wave-particle interactions
• Interpretation of fast particle data from present experiments and projections for burning plasma
D. Momentum Transport and the Origins of Spontaneous Rotation
(J. Rice, T.S. Hahm, P.H. Diamond)
This working group was created in 2007 to increase focus on plasma rotation, which influences transport in a number of ways. Important topics for the 2009 meeting include:
• Toroidal momentum transport, especially non-diffusive mechanism, off-diagonal contributions, etc.
• Cross coupling between particle transport and momentum transport
• Influence of edge plasma properties on spontaneous rotation and momentum transport
• Poloidal momentum transport in low collisionality plasmas
• Integrated modeling of spontaneous rotation
Note: This year the Core and Momentum groups will hold a joint session on the relation between particle and momentum transport, especially the physics of the density and toroidal velocity pinches.
E. Verification and Validation Working Group
(P.W. Terry, W. Nevins)
The Verification and Validation Group has been charged with examining verification and validation (V&V) as it has been defined and structured generally and in other scientific fields, and with formulating V&V procedures and practices applicable to the range of numerical modeling activities within the U.S. Fusion Program, taking into consideration the goals, expectations and desired outcomes of different modeling activities, and resource limitations that are likely to apply to verification and validation. Verification and validation were discussed at a town hall meeting in 2007 and 2008 as part of an effort to examine the state of the art of experiment/model comparison, to confront and seek solutions to particular challenges in performing validation in fusion, and to begin forging consensus about what validation in fusion should be and should accomplish. The town hall meeting was organized by a focused task group that this year seeks to broaden its base and help formulate ideas for validation campaigns involving experiment, modeling, and theory. It is hoped that these efforts will evolve into a cross-cutting working group that interacts in the other TTF working group sessions to advance validation as a common exercise in physics, and meets less frequently to handle technical issues specific to verification and validation.