Formations of complex structures observed during the instability instigated expanding capacitive mode of RF discharge in a linear vacuum vessel, in the absence of an externally applied magnetic field or any other additional constraint applied. Systematic measurements of the plasma parameters, using multiple probe diagnostics, carried out to investigate the parametric dependence of sheath development reveal visible cylindrical tube like multiple double-layer formations around a mesh-type cylindrical plasma source. Such firetube formations provide many interesting and vital information on expanding radio frequency (RF) plasma sheath, charge particle trapping and the associated sheath instability with the RF discharge. The sheath structures, glowing spot formations, space charge formations, complex structure and firetube formations in the expanding plasma are some of the features discussed here in relation to such an expanding RF discharge. Low-frequency sheath instabilities are also observed in connection to the firetube formations using a coaxial mesh-type cylindrical plasma source powered at an operating frequency of 13.56 MHz. The ion acoustic frequency-dominated instability is identified as a sheath-plasma instability associated with the RF plasma.

在不存在外部施加的磁场或施加任何其他附加约束的情况下，在不稳定性期间观察到的复杂结构的形成促使RF真空容器中的RF放电扩展了电容模式。使用多个探针诊断程序对血浆参数进行系统测量，以研究鞘管发育的参数依赖性，从而揭示了可见的圆柱形管，如网状圆柱形等离子体源周围的多个双层结构。这样的火管结构在扩展射频（RF）等离子体鞘层，电荷粒子捕获以及与RF放电相关的鞘层不稳定性方面提供了许多有趣而重要的信息。鞘结构，发光点结构，空间电荷结构，复杂的结构和膨胀的等离子体中的火管形成是此处讨论的有关这种膨胀的RF放电的一些特征。使用以13.56 MHz的工作频率供电的同轴网状圆柱形等离子源，在与火管地层的连接中也观察到了低频鞘管不稳定性。离子声频为主的不稳定性被确定为与RF等离子体相关的鞘膜-等离子体不稳定性。