In backward-wave oscillators (BWOs) with strong end reflections a number of
standing waves with different axial indices can be excited. The theory des
cribing the interaction of such modes is developed. The region of stable si
ngle-mode oscillations is determined and various hysteresis effects which m
ay occur during the voltage rise and fall times are analyzed. (C) 2000 Amer
ican Institute of Physics. [S1070-664X(00)00204-4].