Extending the Capabilities of the Shoelace Antenna on Alcator C-Mod
POSTER
Abstract
The mission of the Shoelace antenna is to couple to short-wavelength edge fluctuations in order to study their properties, possible open- and closed-loop control, and potential exploitation to actively drive transport. The antenna matches both perpendicular wave number and frequency to two such fluctuations: the Weakly- and Quasi-Coherent modes, which regulate transport across the plasma boundary in high-performance, ELM-free, steady-state regimes. In initial operation, the antenna induced a drift-wave-like edge mode [Golfinopoulos \emph{Phys. Plasmas} '14], but no measurements were available to assess resultant transport. Here, we present two upgrades to the system. The antenna's pitch angle was adjusted such that, when field-aligned, the antenna maps to the Mirror Langmuir Probe [LaBombard \emph{Phys. Plasmas} '14], providing detailed fluctuation, profile, and transport measurements. In addition, antenna power has been quadrupled to $\geq$8~kW, increasing driven mode amplitude and reach up the pedestal.
*This work is supported by USDoE award DE-FC02-99ER54512.