行波管放大器中的电子混沌现象

Chaotic electron motion in a traveling-wave tube amplifier

用自洽方程模拟了波 粒相互作用过程中的电子混沌行为 .结果表明 :随着电流的增大 ,电子在相空间的运动轨道将变得混沌 ,混沌轨道受失谐量的影响 .在时间上 ,电子混沌比场的极限环和混沌振荡出现要早 .与场出现极限环振荡的电流阈值相比 ,出现电子混沌的电流阈值要小 ;在场呈极限环状态的“软”非线性区域 ,电子的混沌轨道占据大部分相空间 ;而在场混沌的“硬”非线性区域 ,混沌轨道则弥漫在整个相空间 .当电流一定时 ,电子的混沌运动图样是不变的 ;在一定的电流范围内 ,场的极限环和混沌振荡特征是确定的 。

On the basis of the self-consistency equations, the chaotic behavior of electr on orbits is studied numerically in a traveling-wave tube amplifier. The result s show that motion orbits of electrons in phase space can become chaotic as the cu rrent increases, and the chaotic orbits are affected by the detuning. In t emporal scale, appearance of chaotic motion of electrons is earlier than one of limit cycle and chaotic oscillation of the field. In comparison with the limit c ycle oscillation of the field, the threshold current for the onset of chaotic or bits of electrons is low. In the soft nonlinear regime at which the field exhibi ts limit cycle oscillation, the chaotic region increases and gradually engulfs the whole phase space as the current increases. In the hard nonlinear regime a t whi ch the field exhibits chaotic behavior, the chaotic orbits of electrons occupy a lmost everywhere in the phase space. The pattern of chaotic motion of electrons is unchanged for a certain current; the characteristic of the limit cycle and chaot ic oscillation of the field is certain, but their output power is uncertain in a certain current range.