The effect of tube geometry on the chiral plasma

Abstract

A chiral plasma plume has recently been reported inside a circular quartz tube without the use of an external magnetic field. It is believed that the quartz tube plays an important role in the formation of the chiral plasma plume. In this paper, to better understand how this interesting structure is generated, the effect of the tube geometry on the chiral plasma is investigated. First, the effect of the thickness of the tube wall on the chiral plasma is investigated. It is interesting to find that a too thin or too thick tube wall is not favorable for generating the chiral plasma. The chiral plasma plume can be obtained only at the tube wall thickness of 2 mm. Second, the effect of the diameter of the tube on the chiral plasma is investigated. It is found that, when a tube with an inner diameter of 2 mm is connected with a tube with an inner diameter of 4 mm and the high voltage electrode is placed in the tube with an inner diameter of 2 mm, a diffuse plasma is generated in the tube with an inner diameter of 2 mm, it propagates into the tube with an inner diameter of 4 mm, and a chiral plasma can be obtained at a distance of about 2 cm away from the joint of the two tubes. Third, to further understand how the tube diameter affects the appearance of the chiral plasma, horn shaped tubes with different opening angles are tested. It is found that, when the opening angle is 5 , the chiral plasma formation in the straight part of the tube can maintain the chiral shape and keep propagating in the horn shaped tube but with a much longer pitch. Fourth, to disrupt the axial symmetry, square quartz tubes are used. No chiral plasma can be obtained in the square quartz tubes under all experimental conditions. In addition, when a circular quartz tube is connected with a square tube, the chiral plasma formation in the circular quartz tube changes to a straight plasma plume in the square tube. Finally, the high voltage electrode is placed away from the center of the circular tube to disrupt its symmetry, and it is found that the chiral plasma plume can always be seen even if the high voltage is placed next to the inner wall of the tube.

Periodic forced flow in a nanosecond pulsed cold atmospheric pressure argon plasma jet

“…Plasma helical and double helical stationary structures with helium CAPPJ have been previously reported in the literature [61,92]. We assume that this is also a direct consequence of the forced BFS flow by the periodic plasma perturbations.…”

“…This is also true for the Neon plasma plumes in [53], with variations between helical structure and hairpin like structure, depending on the flow rate-PRF couple. For the chiral plasma (helical shape) reported in [92], the authors are also in the case of a BFS flow geometry, with the use of two connected capillaries of different diameters.…”

Helical streamers guided by surface electromagnetic standing waves

“…As a special form of streamer discharge, low-temperature plasma jet can produce non-equilibrium plasma that is rich in various active particle components at room temperature, and has potential applications in biomedicine, material synthesis and environmental protection [6][7][8]. While in recent experiments on low-temperature plasma jets [9,10] and low-pressure dielectric tube discharges [11][12][13][14], it was found that under the modulation of pulse power supply to specific parameters, the initial plasma discharge channel propagating linearly in the beginning would appear to have discharge mode conversion, forming a three-dimensional (3D) helical plasma structure. Through images captured by high-speed ICCD (intensified charge coupled device) camera, it was found that this seemingly continuous plasma helix was composed of a helical luminous ionized head, which steadily advanced at high speed [11].…”