The Pre-shot Entry form was created by the DAAG group to allow Session Leaders to display and communicate information to the operations group before a shot is performed. Session Leaders can use this form to enter and display values for specific variables, other variables defined by the Session Leader, and a pre-shot comment. Session Leaders can also use the form to make post-shot comments for previous shots. All entries made by the Pre-shot Entry form are automatically entered into the logbook. The newest version of EFIT, “ 05/13/2013” was installed on the Star cluster. The new version defaults the new magnetic data digitizer bit noise for shots > 152000 to be at the same level as DIII-D shots from previous years. Both magnetic (EFIT01) and MSE (EFIT02) EFITs have been rerun for all 2013 shots with this new version. Backups of the original data have been moved to the next available MDSplus trees for each shot.
The newest version of EFIT, “ 05/13/2013” was installed on the Star cluster. The new version defaults the new magnetic data digitizer bit noise for shots > 152000 to be at the same level as DIII-D shots from previous years. Both magnetic (EFIT01) and MSE (EFIT02) EFITs have been rerun for all 2013 shots with this new version. Backups of the original data have been moved to the next available MDSplus trees for each shot.
The formulation of a new code, RMPtran, to calculate the quasilinear transport from external Resonant Magnetic Perturbations has been completed. RMPtran will take the linear collisional Braginskii two fluid responses from the M3DC1 code to calculate the instantaneous non-ambipolar particle transport and JxB torque density for toroidal angular momentum (TAM) transport. These flows, as well the energy transport flows, are bilinear in the screened external magnetic perturbations and can easily be compared with the TGLF model transport flows from internally drive turbulent perturbations. The eventual focus of RMPtran will be on understanding the DIIID RMP density pump out effect: when the RMP coils are switched on, why does most of the TAM leave the plasma by particle convection rather than slowing the toroidal rotation as expected. In many cases, with the pumpout, the density is halved almost doubling the temperature and the rotation sometimes increases slightly. RMPtran, like TGLF, can be called by a transport code.
The GYRO code has been extended to consider kinetic species with an isotropic slowing-down distribution in velocity space in addition to the previously available Maxwellian form. The slowing-down distribution is more appropriate for modeling fusion alpha particles. The goal is to determine what impact the change has on the stability of local and global alpha-driven Alfvén eigenmodes, particularly in sample ITER discharges. Limited, preliminary cases show a modest reduction in growth rate and no change in the real frequency when the slowing-down distribution is used. Further modifications are planned to extend to anisotropic distributions appropriate for neutral beam ions.
Albert Mollen, a graduate student at Chalmers University in Sweden, is visiting GA this month to work on and improve the automated calculation of gyrokinetic eigenvalue spectra for DIII-D profiles. Dominant and subdominant modes can be computed with the eigenvalue solver over a range in wavenumber, and tracked across the minor radius. The resulting contour maps of branch-specific growth rates are a powerful tool for understanding the character of a given discharge versus radius. Albert is refining various script-based tools so they can be integrated into GACODE.
A new UCSD-supported postdoctoral researcher, Olivier Izacard, has begun a long-term visit with the GA theory group. He will be supervised by Chris Holland, and working on a new project aimed at investigating the basic physics of coupling between drift-wave turbulence and tearing modes, collaborating with both the GA theory group and Prof. Dylan Brennan at the University of Tulsa.
A workflow has been implemented within the OMFIT framework to find self-consistent steady-state scenarios for DIII-D. An important tokamak integrated modeling application is the development and design of baseline and advanced operation scenarios using validated equilibrium, transport, stability, and pedestal physics models and available heating and current-drive sources. The OMFIT framework is particularly well suited to support this type of integrated modeling activity. Typically, the workflow starts with a reconstruction of the experimental equilibrium, sources and transport (a ‘kinetic EFIT’). Predictions of the kinetic profiles are subsequently carried out using the TGYRO transport code (using TGLF/GYRO and NEO for the turbulent and neoclassical transport). Self-consistency between the profiles predictions and the equilibrium is obtained by iterating the kinetic profiles and equilibrium between TGYRO and EFIT. As a test application, both an L-mode and H-mode DIII-D discharges have been modeled. Initial results are promising, as a consistent solution could be found within a few iterations.
These highlights are reports of research work in progress and are accordingly subject to change or modification