Competition of modes in a rising-sun magnetron

A special consideration is given to the condition under which the competition of modes may exist in a rising-sun pi-mode magnetron as well as to the prerequisites to the stable generation operating on a mode. It is shown, when the space harmonic spectrum contains a pi-mode component with a zero azimuthal number the probability of decreasing its competitiveness tends to grow. The reason why it happens is that if the HF homogeneity of a rising-sun system is disturbed, it may bring about significant radiation losses due to the transformation of an zero-component into a H₁₁ wave.