Dependence of ELM Size on Rotation at High-Triangularity and High Beta-Poloidal in the DIII-D Tokamak

The effect of rotation on edge localized mode (ELM) size and frequency was studied in the DIII-D tokamak. The regime chosen was one where JT60-U, ASDEX-U and JET reported evidence of rotational dependence to ELM stored energy loss ($\Delta W_{\rm ELM}$) and frequency ($f_{\rm ELM}$), changing from low-frequency, high heat-flux Type-I at high-rotation to the high-frequency, low-heat flux ``grassy" ELMs at low rotation. In DIII-D the experiments were performed at triangularity ($\delta$) $> 0.7$, $\beta_p > 1.6$, $q_{95} > 6$ and with a broad edge rotation scan (+90 to -70~km/s). In the DIII-D experiments, the ELM frequency was found to be weakly dependent on rotation and the ELMs appeared to be always Type-I ELMs. Comparison of $\Delta W_{\rm ELM}$ and $f_{\rm ELM}$ to discharge parameters ($P_{\rm aux}$, $\delta$, $\beta_p$, $q_{95}$) and with other grassy ELM experiments, will be presented. The stability to peeling-ballooning modes and the pedestal height for the ELMs in the rotation scan will be calculated by the ELITE and EPED1 codes. Future grassy ELM experiments in DIII-D based on this analysis will be outlined.