As the core component of space traveling wave tubes, the cathode-heater assembly is required to be stable, reliable, long life and low power consumption. In this paper, an estimation method of thermal contact resistance is proposed, and the thermal characteristics of cathode-heater assembly structure are simulated. Meanwhile, thermal experiment is designed and undertaken, and the whole temperature distribution of cathode-heater assembly structure under a variety of heating power is obtained for the first time. Furthermore, the thermal boundary and excitation of cathode-heater assembly structure is modified, and the values of thermal contact resistances are obtained by interactive method. Finally, a high reliable thermal model of cathode-heater assembly structure is obtained. It is revealed that cathode temperature calculating accuracy is within 5%, and the calculating error of whole structure is less than 72°C .

The interference fit of the three components of the slow wave structure of the space-borne helix trav-eling wave tube,including the clamping rods,tube housing and periodic permanent magnet unit,was mathematically modeled,theoretically analyzed,and numerically simulated in finite element method with software Inventor and AN-SYS.The impact of the mould displacement (extrusion)on the stress,strain,tube’s deformation,and buckling de-formation originated from random fabrication error,was investigated.The calculated and simulated results provide the security scope and success probability of the interference fit.In addition,dependence of the interference fit on the length and thickness of the tube housing was also simulated.The interference fit was found to strongly depend on the thickness,but weakly on the length of the tube;the thinner the tube,the weaker the yield strength,and the higher success probability.

The design of the slots on cathode supporting cylinder of the cathode-heater assembly,used as the e-lectron beam source of space-borne traveling wave tubes (TWTs).First,the heat flow field in the cathode-heater as-sembly was modeled,measured with the lab-built test platform,and simulated in finite element method with ANSYS software.The measured and simulated results show that the accuracy of the calculated cathode temperature is better than 5%,and the calculation discrepancy of the whole cathode-heater assembly is within 72℃.Next,the impact of the slots,including its number,size,position,and orientation,on the heat flow and cathode temperature was investi-gated by thermal simulation.Finally,the current slot design was optimized and the novel heater-cathode assembly with the optimized slots was simulated.The simulated results show that the heating efficiency of the new heater-cath-ode assembly,with reliable mechanical properties,increased by 1 5.2%.