Study of the Influence of Stray Magnetic Fields on the Operation of the European Gyrotron for ITER

In this paper, the influence of stray magnetic fields (SMFs) in the ITER electron cyclotron resonance heating and current drive (ECRH-CD) building on the operation of the European (EU) 170 GHz, 1 MW, continuous wave gyrotrons is investigated. There are mainly two sources of SMF in the ITER ECRH-CD building: 1) the tokamak and 2) the neighboring gyrotrons which are placed in close proximity. The possible electron beam degradation caused by the influence of the SMF is numerically investigated. Furthermore, the collector operation under the influence of an SMF is also studied. A proposal to compensate the influence of the SMF is discussed.