Measurements of Electron Cyclotron Emission from High-Density Tokamak Plasmas in TFR

We present measurements of the electron cyclotron emission from high-density ($n_{e0\mathrm{}}>3\mathrm{}\times {10}^{19}$ ${\mathrm{m}}^{-3\mathrm{}}$) low-runaway plasmas produced in the TFR tokamak device. The emission is, as predicted, self-absorbed, but contrary to expections is the same both along a major radius and along a vertical chord, is the same in both the extraordinary and ordinary modes, and peaks at the plasma frequency and, in addition, at $n$ times the electron cyclotron frequency (for $n=1, 2, 3, 4$). We compare the measurements with the predictions of theory.