One‐dimensional fluid model for a planar sheath in front of a negative ion‐emitting electrode surface immersed in a collision‐less, non‐magnetized, electronegative plasma is presented. It was found that the positive ion speed at the plasma–sheath boundary (PSB) increases linearly with negative ion emission from the electrode but attains a saturation value as soon as a virtual cathode is formed near the electrode surface. The effect of negative ion emission on the pre‐sheath region shows that the potential drop increases across the pre‐sheath in accordance with the rise in positive ion speed at the PSB. The sheath width obtained using the present model shows a similar trend as the Child‐Langmuir law, but its magnitude is found to be consistently higher compared with a non‐emitting electrode. A plausible explanation has been given to explain these effects.

中文翻译：

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负离子发射电极的等离子体-鞘层边界处的正离子速度

提出了浸没在无碰撞，未磁化的负电性等离子体中的负离子发射电极表面前面的平面鞘层的一维流体模型。研究发现，等离子体-鞘层边界处的正离子速度会随着电极中负离子的发射而线性增加，但一旦在电极表面附近形成虚拟阴极，其饱和度值就会达到饱和。负离子发射对鞘前区域的影响表明，随着PSB上正离子速度的升高，整个鞘前的电势降会增加。使用本模型获得的鞘管宽度显示出与Child-Langmuir定律相似的趋势，但发现其幅度始终高于不发光电极。