Recently, a team led by Professor LYU Bo and Dr. BAE Cheonho from Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences, developed a new code that analyzed the multi-fluid plasma rotation and transport properties in tokamak plasmas, including The Experimental Advanced Superconducting Tokamak (EAST).
The result was published in Computer Physics Communications.
"We named this computational code TransROTA," said Dr. Bae, it provides calculations of all torque terms in the angular momentum balance in toroidally-rotating tokamak plasmas, consequently increasing the prediction accuracy of unmeasurable ion velocities and allowing investigations of many interesting plasma physics."
Plasma rotation plays a vital role in fusion experiments, specifically in controlling Magneto-hydrodynamics instabilities, suppressing turbulence growth, and influencing processes like L-H transitions and impurity transport. Predicting and controlling plasma rotation speed is a key challenge for achieving stable and high-performance operation.
In this research, researchers modified Stacey-Sigmar's plasma rotation model to make it less vulnerable to numerical instability, applied upgraded numerical schemes, and tested it with various EAST discharges.
The modification improved the resilience of new couplings among all solved equations against numerical blow-up. The effectiveness of this synchronization was verified, making the code suitable for most plasmas generated by modern tokamaks.
As a result, TransROTA became a user-friendly code that not only calculated rotation velocities of important ions but also predicted individual torques in the angular momentum balance. The available calculations from TransROTA offered an excellent tool for investigating detailed physics and can be used in combination with the reduced model approach to maximize its capability.
The development of this program lays the foundation for further conduct theoretical and simulation research, according to the team.
Relative comparison of all torque terms in fluid-based angular momentum balance of toroidally-rotating tokamak plasmas (Image by BAE Cheonho)
