Evidence for excitation of suprathermal electrons ( $E_{\gamma }\sim 20–100\mathrm{keV}$) during magnetic reconnection in the T-10 tokamak is presented through analysis of the x-ray measurements with enhanced spatial and time resolution. A toroidally viewing x-ray imaging system and a fast hard x-ray detector placed inside the tokamak vessel allow identification of bursts of the nonthermal x-ray radiation around $X$ points of the $m=1\mathrm{}$ and $m=2\mathrm{}$ magnetic islands during the sawtooth crash and prior to the energy quench at the density limit disruption.

• Received 31 July 2000

DOI:https://doi.org/10.1103/PhysRevLett.86.3036