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arXiv 1808.09646physics.plasm-ph
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改进空心阴极辉光放电中磁场控制的电子鞘层演化

Electron sheath evolution controlled by a magnetic field in modified hollow cathode glow discharge

R. Rane, S. Chauhan, P. Bharathi, K. Nigam, P. Bandyopadhyay, S. Mukherjee

摘要:

本文研究了改进空心阴极源直流磁化等离子体中电子鞘层的形成。放电由两个平面平行的阴极和一个小立方体的阳极放在离轴的中心。氩等离子体的产生和响应于鞘层形成阳极附近的等离子体的属性进行了研究,使用电气和光学诊断。研究了气压、磁场对放电电流、等离子体电位、等离子体密度和电子温度等放电参数的影响。放电显示在临界外加磁场下阳极辉光的开始,表明电子鞘层和双层的形成。放电电流最初降低;然而,当阳极上出现阳极斑点时,放电电流再次开始升高。阳极辉光形成的临界磁场取决于工作压力和放电电压。用朗缪尔探针和光谱诊断方法详细研究了离子鞘层到电子鞘层的转变过程。阳极附近的等离子体电位在从离子鞘层向电子鞘层过渡的过程中降低。当阳极斑点完全形成时,等离子体电势锁定在氩气的电离电势上。系统的研究表明,在转变过程中,电子温度升高,等离子体密度下降的散装等离子体。放电的光谱显示存在强的氩原子和离子线。这些谱线的强度在两个鞘层之间的过渡期间显示出下降。在形成阳极斑点之后,由于电子鞘层中增强的电离和激发过程,在放电电流和浮动电位中观察到5-20 kHz量级的振荡。

英文摘要:

The electron sheath formation in a DC magnetised plasma of modified hollow cathode source is studied. The discharge consists of two plane parallel cathodes and a small cubical anode placed off axis at the center. The argon plasma is produced and the properties of the plasma in response to the sheath formation near the anode are studied using electrical and optical diagnostics. In particular, the effect of pressure, magnetic field on discharge parameters such as discharge current, plasma potential, plasma density and electron temperature is studied. The discharge showed an onset of anode glow at a critical applied magnetic field indicating the formation of electron sheath and a double layer. The discharge current initially decreases; however it starts to rise again as the anode spot appears on the anode. The critical magnetic field at which anode glow formation takes place is dependent upon operating pressure and discharge voltage. The transition from ion sheath to electron sheath is investigated in detail by Langmuir probe and spectroscopy diagnostics. The plasma potential near the anode decreases during the transition from ion sheath to electron sheath. The plasma potential locks to the ionization potential of argon gas when anode spot is completely formed. A systematic study showed that during the transition, the electron temperature increases and plasma density decreases in the bulk plasma. The spectroscopy of the discharge showed presence of strong atomic and ionic lines of argon. The intensity of these spectral lines showed a dip during the transition between two sheaths. After the formation of the anode spot, oscillations of the order of 5-20 kHz are observed in the discharge current and floating potential due to the enhanced ionisation and excitation processes in the electron sheath.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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