Recently Discovered Features of the Quasi Coherent Mode*

The Quasi Coherent Mode (QCM) is observed when the EDA H-Confinement regime is produced by the Alcator C-Mod machine and has been found [1] to 1) have a phase velocity in the direction of the electron diamagnetic velocity in the plasma reference frame 2) involve relatively high electron temperature fluctuations 3) be highly localized radially at the outer edge of the plasma column beyond the Last Closed Magnetic Surface (LCMS). A novel theoretical model is given for which; a) the relevant resistive mode driving factor is the sharp plasma pressure gradient that develops at the edge when the plasma enters the EDA H-Regime; b) the known ``disconnected mode approximation'' [2] cannot be applied to characterize the mode topology as the rotational transform $\iota\left(\psi\right)=1/q \left(\psi\right)=0$ on the LCMS; c) the mode localization in the poloidal direction (ballooning) is related to the limited region around the equatorial plane where the pitch of the magnetic field is about constant. The observed temperature fluctuations are consistent with the low values of the local longitudinal thermal conductivity. *Sponsored in part by the US DOE.\\[4pt] [1] B. Labombard, \textit{Bull. Am. Phys. Soc.} 58, (2013) 367.\\[0pt] [2] B. Coppi and G.Rewoldt, \textit{Phys. Rev. Lett.} 33, (1974) 3129.