OBSERVATIONS OF INFRARED RADIATION DURING DISRUPTIONS IN TEXTOR - HEAT PULSES AND RUNAWAY ELECTRONS

Disruptions are studied in TEXTOR using two infrared cameras. In the t hermal quench phase, fast changing heat fluxes are observed, each deli vering energies larger than 1 kJ/m(2) to the limiter. These bursts are correlated with an electron temperature pulse near the limiter and an increased release of impurities. Further bursts are observed in the c urrent decay phase. For the first time a disruption generated beam of runaway electrons, accelerated in about 10 ms to about 20 MeV, is obse rved inside the plasma by the infrared synchrotron radiation. This bea m carries a current of about 20 kA and is lost within approximately 10 0 mu s. The heat deposition on the limiter due to the runaways is comp arable to the power flux by the heat bursts.