Theory Weekly Highlights for August 2017

August 25, 2017

A third code-camp for developers (see (OMFIT_Camp_August_2017.pdf)) of the OMFIT data analysis and modeling framework was hosted by O. Meneghini and S. Smith at General Atomics this week (See Highlight from August 18 2017). Numerous bug fixes and improvements were made to the framework itself. For example, under the guidance of S. Flanagan support for writing data to MDS+ was added at the framework level. Significant progress was also made on a broad range of its physics modules. J. Candy, B. Grierson, and C. Holland developed a module for the GYRO gyrokinetic code and for the new flagship CGYRO gyrokinetic code. D. Eldon refined the SOLPS module in OMFIT, which now interfaces with some of the details of the EIRENE kinetic neutral code . The OMFITprofiles module has been sped up by S. Haskey by parallelizing the data fetching of DIII-D CER data and, thanks to D. Eldon and N. Logan, OMFIT now features a spline fitting method with Monte-Carlo error propagation. Significant advancements were also made by T. Wilks with the BOUT++ module, which, thanks to the efforts of M. Kostuk, now supports execution on the GA IRIS cluster in addition to NERSC and is now capable of directly mapping the kinetic profiles from the OMFITprofiles module onto the BOUT++ 2D mesh and provides efficient methods for visualizing both input and output data. The TRIP3D_GPU module has been re-written by G. Trevisan to efficiently aggregate the results of multiple simulations (run in parallel across multiple GPUs across distributed servers) for studies of divertor footprints. K. Thome continued to make improvements to the ICE module. J. McClenaghan, A. Tema, and G. Snoep worked on different aspects of a larger whole device modeling effort. Specifically, J. McClenaghan focused on improving the TORBEAM module, A. Tema on interfacing a neural-network based model of the NEO drift-kinetic bootstrap current model, and G. Snoep on coupling the STRAHL impurity transport code with the OMFIT core-pedestal coupled TGYRO-EPED workflow. Finally, several come-byers briefly joined the code-camp as they were casually attracted by the great refreshments. The next community meeting will be at APS, where a room has been reserved for general OMFIT-related discussion (exact time and location to be communicated). Tentatively, the next code-camp will be held the second week of DIII-D LTO3 (May 7-11 2018). A series of hand-on tutorials are also being planned.

August 18, 2017

A new version (v0.21) of OMFIT has been released. Amongst the many physics module updates, the ONETWO transport code has been added as an option (in addition to TRANSP) to perform the power balance analysis required for creating time dependent kinetic constraints for EFIT. Another notable update is the ability to run the TORBEAM beam-tracing code to evaluate the time dependent density cutoff headroom for existing DIII-D shots. Numerous updates were aimed at increasing the framework robustness, ease of use and improve the documentation.
Preparations are under way for the third OMFIT code-camp, which will be hosted at General Atomics the week of August 21st. This event provides a focused opportunity for users and developers to address outstanding issues, make progress on the development of the physics modules, and bring new ideas to life. The participants will be able to take full advantage of the community support by self-organizing in topical groups and learning from each other. All are welcome to join to share input, contribute to existing modules, and integrate analyses within the OMFIT ecosystem.

August 11, 2017

A seamless formula was obtained for calculating the stopping force and energy deposition of fast, but non-relativistic, electrons moving through a cold plasma by breaking the problem into two parts, a Schrodinger equation solution for close collisions and a modified Born approximation for distant collisions, and summing the two contributions. The formula corrects and improves the usual Coulomb log formulas developed by Yokota, Deutsch, Betti, and others.

August 04, 2017

Yueqiang Liu returned from a visit to the ITER IO from July 3 through 25. At ITER, he carried out collaborative research work with Alberto Loarte and others, modeling the plasma response to the resonant magnetic perturbation fields, applied for the purpose of controlling type-I ELMs in ITER. The study was carried out for five ITER plasma scenarios, according to the ITER operational plan covering the Hydrogen phase down to the full current full field DT phase.

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