Factors influencing the temporal growth rate of the high order TM0n modes in the Ka-band overmoded Cherenkov oscillator

摘要

When the wavelength of overmoded Cherenkov oscillator goes into Ka-band, power handling capacity becomes an essential issue. Using the TM02 mode or higher order TM(0n)modes as the operating mode is a potential solution. This paper is aimed to find some proper parameters to make the temporal growth rate of the TM02 mode higher in our previously studied Gigawatt (GW)-class Ka band oscillator. An accurate and fast calculation method of the "hot" dispersion equation is derived for rectangular corrugated SWSs, which are widely used in the high frequency Cherenkov devices. Then, factors that affect the temporal growth rate of the high order TM0n modes are analyzed, including the depth of corrugation, the radius of drift tube, and the diode voltage. Results show that, when parameters are chosen properly, the temporal growth rate of the TM02 mode can be as high as 0.3 ns(-1). (C) 2015 AIP Publishing LLC.