An analysis of the ECRF stray radiation in JT-60SA

Introduction. The JT-60SA large superconducting tokamak being jointly built by Europe and Japan [1] under the Broader Approach agreement will start operation in 2020. It is designed to address many areas of fusion science in preparation of the burning plasma of ITER and DEMO, in particular the ones related to the control of high ? steady state plasmas and the confinement of high energy particles. A key tool in the machine is the 7 MW, 9 gyrotrons ECRF system which, as for the 34 MW NBI system, will be available at full performance in the Integrated Research Phase. The ECRF system will support plasma operations from the very beginning for EC assisted start-up, EC wall conditioning, bulk heating and later on current drive and magneto-hydrodynamic instabilities control. In order to allow the needed flexibility the ECRF system will operate at three different frequencies, 82, 110 and 138 GHz.