Observation of n$>$1 Mode During ELM-Driven RWM Experiments in DIII-D

In recent resistive wall mode (RWM) experiments in DIII-D, edge localized modes (ELMs) were found to trigger RWMs in high rotation plasmas, which are well above the rotation threshold [1]. Interestingly, the ELM-induced $n$=1 perturbations are almost always accompanied by significant amounts of $n$=3 modes. While an $n$=1 ELM-driven RWM grows but can be suppressed by active feedback, the influence of $n$=3 mode needs to be investigated. A clear example that an ELM-driven $n$=3 mode grew without being hindered by $n$=1 feedback will be presented. It is noteworthy that the $n$=3 mode appeared to cause $\beta $ and rotation collapses, similar to $n$=1 RWM. Detailed MHD analysis is in progress to investigate whether the $n$=3 mode is attributable to $n$=3 RWM in the vicinity of $n$=1 wall-stabilized plasmas [2]. We will discuss the stability calculation results and the details of the $n$=3 mode observation. [1] E.J. Strait, \textit{et al., }Bull. Am. Phys. Soc. \textbf{50}, 79 (2005). [2] Y. In, \textit{et al., }to be submitted for publication.