A new CW-load for high power ECRH systems

Plasma heating at upcoming thermonuclear fusion experiment facilities will be partially performed by large Electron Cyclotron Resonance Heating (ECRH) installations. The required pulse length is 1000 seconds (ITER specification) and more in order to meet the physical aims at Stellarators and Tokamaks as well. The conditioning and testing of the ECRH sources, high power gyrotrons, is an important task of these installations. CW operation under full power conditions requires a microwave load with a power level in the range of 1 MW. In the ECRH system at W7-X several types of loads are in operation but their long term stability needs to be improved. A new approach of load design will be discussed which is currently under test.