DIII-D–WEST Similarity Experiments for High-Performance Long-Pulse Operation: H-mode Access and High Beta-N Sustainment
2025 Research Campaign, Task Force: W Compatible Steady State Scenarios
Purpose of Experiment
Similarity experiments between DIII-D (USA) and WEST (France) aim to study the underlying physics of accessing high-fusion performance (with an edge transport barrier and high core ion temperature/pressure), which will be applied to long-pulse WEST machines with tungsten walls. DIII-D, an extremely well-diagnosed facility, is uniquely suited to address relevant physics questions (H-mode access and high N sustainment) for future applications with metallic walls. WEST has developed a sawtooth-free, long-pulse scenario with a hybrid-like q-profile (safety factor on-axis, qo slightly above unity), which has been maintained in L-mode edge up to 1337 seconds but with modest fusion performance. We aim to address the key question of how to further optimize fusion performance for long-pulse applications using direct WEST and DIII-D applications (considering that DIII-D will be equipped with a tungsten wall) with a vision for ITER operations and fusion power plant designs.