The double-chamber arc plasma torch (DCAPT) is a promising arc source due to its high energy efficiency and low erosion rate. It has been widely used in various fields including coal powder ignition, boiler heavy oil-free ignition, and production of sheet-shaped carbon materials, among others, but research on its micro-discharge characteristics is still insufficient. In this work, a magnetically-stabilized DCAPT with a quartz window on the inner electrode is designed and studied, in order to investigate the effects of magnetic field position and intensity, discharge current, gas flow rate, electrode diameter, and electrode polarity on its discharge characteristics. Results show that both the volt-ampere characteristics and thermal efficiency of DCAPT exhibit a strictly decreasing trend, and both of them can be accurately predicted using similar theoretical approaches. The discharge characteristics of DCAPT differ significantly for different polarities. When in reverse polarity, the outer cathode arc root attaches to the outlet, resulting in an increased arc length and greater randomness in the arc-root fluctuations. As a result, the arc length, voltage, thermal efficiency, and voltage fluctuations are all greater than with normal polarity. Within the experimental range of the parameters, the thermal efficiency of DCAPT is between 40 and 74%. Due to the cathode's “easily mobility” characteristic, the rotation speed of the cathode arc root is always greater than that of the anode, resulting in higher thermal losses for the cathode than for the anode. This is the primary source of thermal loss and the main factor contributing to the rapid erosion of the cathode in the DCAPT. This study reveals the correlation between the volt-ampere characteristics, thermal characteristics, and dynamic evolution of the DCAPT. The research findings have significance for guiding the structural design, parameter selection, and choice of application of this type of plasma torch.

双室电弧等离子炬（DCAPT）由于其高能效和低腐蚀率而成为一种有前途的电弧源。它已广泛应用于煤粉点火、锅炉重油无油点火、片状炭材料生产等领域，但对其微放电特性的研究还不够。本工作设计并研究了一种内电极带有石英窗口的磁稳定DCAPT，以研究磁场位置和强度、放电电流、气体流量、电极直径和电极极性对其的影响。放电特性。结果表明，DCAPT的伏安特性和热效率均呈现严格下降的趋势，并且可以使用类似的理论方法准确预测它们。不同极性的DCAPT放电特性有显着差异。当极性相反时，外阴极电弧根附着在出口上，导致电弧长度增加，电弧根波动的随机性更大。因此，电弧长度、电压、热效率和电压波动都大于正常极性。在实验参数范围内，DCAPT的热效率在40%~74%之间。由于阴极的“易迁移”特性，阴极弧根的转速始终大于阳极的转速，导致阴极的热损失高于阳极。这是热损失的主要来源，也是导致 DCAPT 中阴极快速腐蚀的主要因素。这项研究揭示了 DCAPT 的伏安特性、热特性和动态演化之间的相关性。研究成果对于指导该型等离子炬的结构设计、参数选择和应用选择具有重要意义。