Synchrotron Radiation from the ATC Tokamak Plasma

The synchrotron radiation emitted from the adiabatic toroidal compressor (ATC) tokamak plasma along a major radius was measured over a band of frequencies ($35 \mathrm{GHz}<f<\mathrm{}450\mathrm{} \mathrm{GHz}$ with resolution $\frac{f}{\Delta f}\approx 2$ and rise time $\tau <10\mathrm{}$ μsec) that included the electron cyclotron frequency and its first few harmonics. The radiation is at least 50% polarized (${\overrightarrow{\mathrm{E}}}_{\mathrm{wave}}\perp \overrightarrow{\mathrm{B}}$). Radiation due to runaway electrons increases sharply and coincidentally with the appearance of positive spikes in the loop voltage and decays exponentially after the onset of an $m=2\mathrm{}$ oscillation in the plasma.