Theory Weekly Highlights for November 2016

November 18, 2016

The first OMFIT code-camp took place this week at General Atomics (see Highlight from November 4), with up to 15 developers gathering each day in the GA-theory conference room.. Each day started with a round table discussion where the participants reviewed the accomplishments of the day before, and stated their goals for the day. From this discussion, developers self-organized into small working groups, which efficiently made decisions and progressed in their code development. Co-location allowed more experienced developers to teach the best OMFIT development practices to less seasoned ones. Some of the technical highlights include: B. Lyons's extension of the OMFIT M3D-C1 module to enable routine execution of the code for linear stability and 3D response calculations; J. Candy’s adaptation of the TGYRO module to support particle evolution of individual ion species; initial work by C. Holland to support visualization of GYRO results in OMFIT; development by T. Wilks of a new module to handle 2D SOL grid generations for the BOUT++ code and other modules; and C. Rea’s development of a DATABASE module for directly interfacing SQL databases and machine learning libraries. Significant progress has also been made on the OMFITprofiles, TRANSP, and SCOPE physics modules, as well as the framework itself.

November 11, 2016

The Small Angle Slot (SAS) divertor is the new advanced configuration being installed in DIII-D as an upper divertor. Understanding the accuracy of the intended strike geometry on the divertor will help future experiments to fully exploit the benefits of the SAS. Previous analyses (see highlight for Sept 2 2016 at Theory Weekly Highlights for September 2016) focused on 2D magnetic uncertainty quantification. More recently a preliminary 3D analysis has been carried out using TRIP3D on the reference SAS EFIT equilibrium. By switching on 3D error fields due to the experimentally measured tilts and shifts of the external shaping coils, field lines can be traced in order to investigate the vacuum features of the 3D magnetic topology near the divertor. As expected, the qualitative effect of such 3D error fields is the separation of the stable separatrix manifold from the unstable one, with the consequent appearance of lobe structures and magnetic stochastization. Further, more quantitative, analyses will aim at including the 3D plasma response.

November 04, 2016

At the 58th APS Meeting in San Jose this week Ron Waltz delivered an invited presentation on “A critical gradient model for energetic particle transport from Alfven Eigenmodes” and Val Izzo presented an invited talk on “Parallel Impurity Spreading During Massive Gas Injection.” Rui Ding, Philip Snyder, and Alan Turnbull gave contributed oral presentations, respectively on “Active control of high-Z material erosion in the DIII-D divertor”, Prediction and Optimization of the ITER Pedestal, and “The External Kink Mode in Diverted and Limited Tokamaks”.

Preparations are under way for the first OMFIT code-camp, which will be hosted at General Atomics the week of November 14th. The idea of this event is to have a focused opportunity for users and developers to self-organize into small working groups to address outstanding issues and quickly bring new ideas to life. Co-location and face-to-face conversation will allow participants to take full advantage of the community support. Working groups will be able to work in parallel, and their relatively small size will facilitate efficiency in the decision-making and development processes. OMFIT users and developers of all levels of experience are welcome to join. The code-camp flyer with the link to the agenda can be found at

These highlights are reports of research work in progress and are accordingly subject to change or modification