The Microwave Propagation in a Dust Plasma of a DC Glow Discharge

In a plasma, dust particles acquire negative charges and interact with each other, which may lead to a significant change of the plasma properties. In this paper, a method was proposed and implemented to study the influence of dust particles on the microwave propagation in DC glow discharge plasma. The DC glow discharge device is a glass tube with 50 cm in length and 2.5 cm in diameter, and it can produce plasma with much more accurate parameters and more stable state. When dust particles were put into the plasma, the dust particles could levitate in it, and they can form a periodic and steady structure. The 1-4 GHz antennas were fixed on both sides of the glass tube, and then the microwave can pass through the dust plasma structure. The network analyzer was used to measure the microwave propagating in the plasma before and after adding dust particles to study the attenuation effect of dust plasma with different pressure range from 0.1 to 1 torr and different discharge power. The experimental results show that dust particles can enhance the microwave attenuation, and when the dust particles exist, the attenuation of microwave was more than that in the plasma without dust particles. And the reason for this phenomenon is analyzed.