Thermal Distributions of Multi-Junction Antenna and PAM Antenna

摘要

A multijunction antenna is under development for 4.6 GHz lower hybrid current drive system on experimental advanced superconducting tokamak (EAST). The antenna mouth is exposed to the high temperature plasma directly during tokamak discharge. The thermal distribution of the existing EAST 4.6 GHz multi-junction antenna is analyzed to evaluate the safety of the antenna under high power operation. Result shows that the maximum temperature is 628 ℃ at the antenna mouth. Then the result is also compared with that of a kind of passive active multijunction (PAM) antenna. The water channels in the multi-junction antenna are located on the upper and bottom of each module, while in the PAM antenna they are drilled behind the passive waveguides. The maximum temperature deposited on the port of PAM antenna is just 285.64 ℃, at least two times lower than that of the multi-junction antenna.