ELM Size \& $\nu_{\perp e}\approx 0$ Location During RMP \mbox{H-mode} Plasmas in DIII-D

Previous studies [1,2] examined the correlation between vacuum island overlap region width and edge localized mode (ELM) size during $n=3$ resonant magnetic perturbations (RMPs) in DIII-D. For rotating H-mode plasmas it was proposed [3,4] that the resonant perturbation components would be screened by plasma response except at locations with the sum of the electron diamagnetic and $E\times B$ velocities, $\nu_{\perp e}=0$. One hypothesis for the mechanism of RMP ELM suppression is that the pedestal width is prevented from expanding to the peeling-ballooning instability boundary by plasma modes at a location where vacuum RMP fields penetrate. This would suggest that the $\nu_{\perp e}=0$ location would be closer to the plasma edge during ELM suppression than during ELM mitigation. This paper will examine the degree of correlation between $\nu_{\perp e}=0$ location and ELM size during RMP H-mode plasmas including those from the previous studies. \vskip3pt \noindent [1] M.E.\ Fenstermacher et~al., Phys.\ Plasmas {\bf 15} (2008) 056122.\par \noindent [2] M.E.\ Fenstermacher et~al., J.~Nucl.\ Mater.\ {\bf 390} (2009) 793.\par \noindent [3] M.~Heyn, et~al., Nucl.\ Fusion {\bf 48} (2008) 024005.\par \noindent [4] E.~Nardon, et~al., Nucl.\ Fusion {\bf 50} (2010) 034002.