Calculations of Starting Currents and Frequencies in Frequency-Tunable Gyrotrons

Abstract

Cold cavity and self-consistent formalisms for starting current and frequency calculations in frequency-tunable gyrotrons are summarized. Numerical solution schemes of the corresponding equations are discussed. A specific case is analyzed in detail.

Analysis of oscillation characteristics and optimal conditions for high power operation of Gyrotron FU CW GIII

“…To investigate the physical processes underlying these results, the dependences of the oscillation power and the frequency on several parameters were calculated using a self-consistent code, 8 in which the output power P from the cavity exit and the wave frequency f are calculated by simultaneously solving for both the electron motion and the electric field growth in the cavity. 8 The input parameters for this code are V k , I c , B, the radius of the annular electron beam at the cavity R b , and the pitch factor of the electrons a.…”

“…8 The input parameters for this code are V k , I c , B, the radius of the annular electron beam at the cavity R b , and the pitch factor of the electrons a. The values of R b and a were determined from electron trajectories that were calculated using the EGUN code.…”

The Development of 170 GHz, 1 MW Gyrotron for Fusion Application

“…And in Figure 3, we can see that the major competing modes, TE 24,10 and TE 26,10 for TE 25,10 , are fairly well separated. Considering the higher longitudinal index modes, ones can ignore the modes of TE 25,10,2 and TE 25,10,3 , because they have much lower quality factors than the modes whose value of q is 1 (i.e., the TE 25,10,1 mode in the present case) [15,16]. Hence, the TE 25,10 mode was chosen as the operating mode for the…”

The Gyrotron Startup Scenario in the Single Mode Time Dependent Approach

“…Starting current estimation can be done in a classic way [4,10], but it can also be found by iterating the time simulation for different beam current values until stable power at the output and a stable RF field can be observed. This is quite a convenient method as it does not need extra programming, but it does require computation time.…”