Intrinsic connections between thermionic emission cooling effect and emission characteristics of W-La_2O_3 cathodes at high temperatures

摘要

We investigated the effect and mechanism of the emission characteristics on the thermionic emission cooling (TEC) effect using the prepared W-La2O3 cathode in the temperature range of 2050-2350 degrees C. The experimental and calculated results showed that the TEC effect and the current density of cathodes increased non-linearly with temperature. Under high temperatures, the initial velocity of emission electrons provides a significant contri-bution to improving the TEC effect. The emission current flow patterns corresponding to the cathodic emission characteristic region under operating conditions determine the magnitude and trend of the TEC effect, which can be well interpreted by the high-temperature thermionic emission (HTTE) model.