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The twig edge states in graphene‐like structures are viewed as the fourth states complementary to their zigzag, bearded, and armchair counterparts. In this work, a rod‐in‐plasma system in a honeycomb lattice with twig edge truncation under external magnetic fields and lattice scaling is studied and it is shown that twig edge states can exist in different phases of the system, such as quantum Hall (QH) phase, quantum spin Hall (QSH) phase, and insulating phase. The twig edge states in the negative permittivity background exhibit robust one‐way transmission properties immune to backscattering and thus provide a novel avenue for solving the plasma communication blackout problem. Moreover, it is demonstrated that corner and edge states can exist within the shrunken structure by modulating the on‐site potential of the twig edges. Especially, helical edge states with the unique feature of pseudospin‐momentum locking that can be excited by chiral sources are demonstrated at the twig edges. These results show that the twig edges and interface engineering can bring new opportunities for more flexible manipulation of electromagnetic waves. [ABSTRACT FROM AUTHOR]

The discharge properties of post‐cathode plasma generated by grid electrode discharge were investigated. Post‐cathode plasma is the plasma, generated in an open discharge, at the other side of the cathode that is different from the electrode gap. Based on the unique electron transport, discharge chamber parameters were adjusted to compare their impact on the electron density of the post‐cathode plasma. The peak of the electron flow in the grid cathode hole and the peak of the post‐cathode plasma thickness appear in the same diameter of the grid electrode holes, which shows the crucial influence of the electron transport within the grid cathode on the post‐cathode plasma. The study also investigated the combined effects of cathode thickness and gas pressure on post‐cathode plasma thickness. The findings suggest that the primary factor influencing post‐cathode plasma thickness is the electron transport within the grid cathode. [ABSTRACT FROM AUTHOR]

In this work, emission spectra measurements from direct current (DC) reverse‐brush discharge plasmas were used to elucidate the energy level transition processes corresponding to each spectral line based on the mechanism of emission spectrum generation. The axial distribution patterns of the spectral line intensity and the electron excitation temperature in the electrode gap and post‐cathode space were systematically investigated. By comparing the acquired experimental results, it was observed that both the relative intensity of the plasma emission spectra and the electron excitation temperature in the electrode gap were higher than in the post‐cathode space, while their axial distribution trends exhibited an initial increase followed by a decrease. Additionally, the impact of the discharge gas pressure, reverse‐brush electrode thickness, and the number of electrode openings on the emission spectral line intensity and electron excitation temperature in the electrode gap were explored. Explanations for the underlying physical mechanisms were also provided. [ABSTRACT FROM AUTHOR]