Miniaturized non-thermal atmospheric pressure plasma jet—characterization of self-organized regimes
Miniaturized non-thermal atmospheric pressure plasma jet—characterization of self-organized regimes
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DOI：
10.1088/0741-3335/51/12/124045
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发表时间：
2009-12
影响因子：
2.2
通讯作者：
J. Schäfer;R. Foest;A. Ohl;K. Weltmann
中科院分区：
文献类型：
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作者：
J. Schäfer;R. Foest;A. Ohl;K. Weltmann
该研究报告的第一次在射频（RF）等离子体产生的小型化非热大气压等离子体射流的自组织效应。该源被配置为电容耦合RF射流（27.2MHz），其具有围绕石英毛细管（d = 4.0mm）的两个外环电极，气体混合物在石英毛细管之间以0.05- 5slm的典型速率流动。该源的应用背景是用PECVD工艺沉积薄膜。因此，可以在有效放电区域的下游少量添加薄膜产生剂。通常，放电发展的时间分辨观察表明，放电由不同的放电丝，出现stocherous和沿毛细管壁的发展。这种随机模式在大多数情况下都可以很容易地找到。然而，在特殊条件下，准层流建立和控制数量的等距长丝发展，形成固定的离散旋转模式（锁定模式）。本文以Ar为工作气体，对锁模的存在范围进行了系统的研究。通过对等离子体的光发射进行低频分析来研究时间放电行为。射频功率，气体流量和电极距离被解释为缩放参数，负责在非热大气压等离子体射流的自组织。不同的放电制度的外观上描述的现象学的基础上和放电细丝的集体行为解释的基础上的毛细管内的气体流动的放电通道的热干扰。
The study reports for the first time on self–organization effects in a radio frequency (RF) plasma generated with a miniaturized non-thermal atmospheric pressure plasma jet. The source is configured as a capacitively coupled RF jet (27.2 MHz) with two outer ring electrodes around a quartz capillary (d = 4.0 mm) between which a gas mixture flows at typical rates of 0.05—5 slm. The application background of this source is the deposition of thin films with a PECVD process. Therefore, thin film producing agents can be added in small quantities downstream the active discharge region. Commonly, the time-resolved observation of the discharge development reveals that the discharge consists of distinct discharge filaments that appear stochastically and evolve alongside the wall of the capillary. This stochastic mode can be easily found under most situations. However, under special conditions, a quasi-laminar flow is established and a controlled number of equidistant filaments develop which form fixed discrete rotating patterns (locked mode). In this paper, a systematic study is performed using Ar as process gas to define the range of existence of the locked mode. The temporal discharge behaviour is studied by performing a low frequency analysis on the optical emission of the plasma. RF power, gas flow rate and electrode distance are interpreted as scaling parameters that are responsible for the self-organization in the non-thermal atmospheric pressure plasma jet. The appearance of the different discharge regimes is described on a phenomenological basis and the collective behavior of the discharge filaments is explained based on the thermal interference of the discharge channels with the gas flow inside the capillary.