Synchrotron Radiation from the ATC Tokamak Plasma

Abstract

The synchrotron radiation emitted from the adiabatic toroidal compressor (ATC) tokamak plasma along a major radius was measured over a band of frequencies ($35 \mathrm{GHz}<f<450 \mathrm{GHz}$ with resolution $\frac{f}{\ensuremath{\Delta}f}\ensuremath{\approx}2$ and rise time $\ensuremath{\tau}<10$ \ensuremath{\mu}sec) that included the electron cyclotron frequency and its first few harmonics. The radiation is at least 50% polarized (${\stackrel{\ensuremath{\rightarrow}}{\mathrm{E}}}_{\mathrm{wave}}\ensuremath{\perp}\stackrel{\ensuremath{\rightarrow}}{\mathrm{B}}$). 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 $m=2$ oscillation in the plasma.