arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1906.06255physics.plasm-ph
收藏

外磁场对RF电容放电中粉尘$-$声波的影响

Influence of External Magnetic Field on Dust$-$Acoustic Waves in a Capacitive RF Discharge

Mangilal Choudhary, Roman Bergert, Slobodan Mitic, Markus H. Thoma

摘要:

本文报道了$-$自激尘埃声波在磁化射频放电等离子体中的传播特性。在尘埃等离子体中,当在约束势阱中加入更多的粒子后,可以自发激发出DAW,并发现DAW沿离子流方向传播。这种低频模式的自发激发是可能的,由于不稳定性与通过尘埃颗粒介质的离子流。背景电场和中性气压决定了激发态直驱波的稳定性。外磁场的强度对直拉丝的特性有很大的影响。强度为B $<$ 0.05 T的磁场仅在中等功率和中等气压下(P = 3.5 W和p = 27 Pa)改变尘埃等离子体中的波的传播特性。发现当磁场B $>$大于0.05 T时,直声表面波开始衰减,当磁场B $\sim$大于0.13 T时,直声表面波完全衰减。在将功率和压强分别降低到3W和23Pa后,在没有B的情况下激发的DAW稍微不稳定。在这种情况下,磁场仅稳定和修改了DW的传播特性,而B的强度增加到0.1 T或甚至更高。外磁场对粒子鞘层电场的影响是磁化射频放电等离子体中直序波导发生衰减的主要原因。

英文摘要:

This paper reports experiments on self$-$excited dust acoustic waves (DAWs) and its propagation characteristics in a magnetized rf discharge plasma. The DAWs are spontaneously excited in dusty plasma after adding more particles in the confining potential well and found to propagate in the direction of streaming ions. The spontaneous excitation of such low-frequency modes is possible due to the instabilities associated with streaming ions through the dust grain medium. The background E-field and neutral pressure determine the stability of excited DAWs. The characteristics of DAWs strongly depend on the strength of external magnetic field. The magnetic field of strength B $<$ 0.05 T only modifies the characteristics of propagating waves in dusty plasma at moderate power and pressure, P = 3.5 W and p = 27 Pa respectively. It is found that DAWs start to be damped with increasing the magnetic field beyond B $>$ 0.05 T and get completely damped at higher magnetic field B $\sim$ 0.13 T. After lowering the power and pressure to 3 W and 23 Pa respectively, the excited DAWs in the absence of B are slightly unstable. In this case, the magnetic field only stabilizes and modifies the propagation characteristics of DAWs while the strength of B is increased up to 0.1 T or even higher. The modification of the sheath electric field where particles are confined in the presence of the external magnetic field is the main cause of the modification and damping of the DAWs in a magnetized rf discharge plasma.

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。

↑