Destabilization of diocotron modes inside structured anode cavities
Destabilization of diocotron modes inside structured anode cavities
复制标题
结构化阳极腔内双电管模式的不稳定
DOI：
10.1063/1.873711
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
S. Riyopoulos
中科院分区：
文献类型：
--
作者：
S. Riyopoulos
先前对低空间电荷ωe2/Ω2≪1，E×B的稳定性分析表明，当流动接触阴极（阴极层）时，光滑阳极腔内的漂移流动在缓波ω/ck≪1 diotron不稳定性下实际上是稳定的。本文表明，当阴极层模式的相速度与空腔本征模式相匹配时，周期性结构阳极的存在会破坏阴极层模式的稳定性，因为结构腔在真空中支持慢波。在导向中心近似中得到了一个自洽的包含结构阳极效应的解析色散关系。生长速率与磁控管振荡的发生有关，其尺度为γ/ω ~ ω d /ω≃1/kd；它与ωe2/Ω2→0无关，并且保持有限。最不稳定的频率对应于流表面以下的谐振层（略低于Buneman-Hartree频率），并且发现增长率相对于共振失谐是对称的。
Previous stability analysis of low space charge ωe2/Ω2≪1, E×B drifting flows inside smooth anode cavities has shown that they are practically stable against slow wave ω/ck≪1 diocotron instabilities when the flow touches the cathode (cathode layer). It is shown here that the presence of periodically structured anode destabilizes cathode layer modes when their phase velocity matches that of an empty cavity eigenmode, as structured cavities support slow waves in vacuum. An analytic dispersion relation that self-consistently includes the structured anode effects is obtained in the guiding center approximation. The growth rate, related to the onset of magnetron oscillations, scales as γ/ω∼ωD/ω≃1/kd; it is independent of, and remains finite as, ωe2/Ω2→0. The most unstable frequency corresponds to a resonant layer below the flow surface (slightly below the Buneman–Hartree frequency) and the growth rate is found symmetric relative to the detuning from resonance.