In this work, the Paschen curves and current–voltage characteristics of three large-area short glow discharge structures with grid and solid plate electrodes are studied. The study of the Paschen's curves reveals that Paschen's law is broken for all three investigated electrode structures. It is shown that the experimentally measured Paschen curves are well approximated with a modified Paschen's law. A comparison of the current–voltage characteristics of the short glow discharge in the three types of electrode structures reveals that the use of grid electrodes allows for the increase in the discharge current. The effects of the electrode gap, which were varied from 1 mm to 7 mm, on the Paschen curves and current–voltage characteristics of short glow discharges are also investigated.

A grid anode glow discharge is a promising source of plasma for absorbing electromagnetic radiation. This paper presents an experimental study of a large-area dc grid anode glow discharge in helium. The behavior of the helium discharge was studied at pressures in the range of 2–50 Torr and discharge voltages up to 1500 V. It was observed that the discharge completely covered the cathode surface at helium pressures of 2–25 Torr. For all pressures, voltage increases as current increases, which typical for anomalous glow discharge. The electron density in the post-anode plasma and attenuation of the microwave radiation by the plasma were measured using microwave diagnostic methods. It was found that the electron density and degree of helium ionization decrease with increasing helium pressure and increase with increasing discharge current. The electron density in the post-anode plasma is not high: n_e is about 2 × 10⁹–6 × 10¹⁰ cm^–3, corresponding to a degree of ionization of about 10^–7–10^–6. It is shown that the maximum attenuation of 10-GHz microwave radiation is about 6% at a helium pressure of 2 Torr.

In a previous study, the characteristics of plasma generated by fast electrons behind a grid anode with short glow discharge were studied using numerical simulation. The source of the post-anode plasma electrons is considered to be the direct current glow discharge itself in the gap between a cathode and a grid anode. However, the electron attenuation of the microwave radiation in the post-anode space measured in experiments does not correspond to the numerical predictions. In this paper, the current–voltage characteristics of the short glow discharge with a grid anode and the spectral characteristics of the discharge in both the electrode gap and the space behind the grid anode are studied; the effective thickness of the plasma in the post-anode space is estimated using a spectral method.

This paper presents a new composite grid electrode structure for the generation of plasma that is suitable for modeling microwave radiation transmission through atmospheric plasma. The new grid anode-composite cathode (GA-CC) structure is to be contrasted with the ordinary grid anode-cathode plate (GA-CP) structure. It is found that the breakdown voltage of the new GA-CC electrode structure is lower than that of the GA-CP structure and is a bit shifted to the right on the Pd -axis. An advantage of the GA-CC structure over the GA-CP structure is that it requires a lower voltage to generate the same current. It is found that plasma generated by the new GA-CC structure selectively strengthens electromagnetic waves attenuation in the frequency range of 9–12 GHz.

Plasma antenna systems consisting of discharge elements have great practical application prospects due to their ability to quickly adjust parameters over a wide range. In this work, the radiation patterns of a 30 mm long linear antenna surrounded by 16 standard T8 fluorescent lamps were measured by using a spectrum analyzer with a tracking generator. The radiation pattern of the system is measured by connecting the output of the spectrum analyzer tracking generator to a linear antenna and connecting the input of the spectrum analyzer to the receiving broadband horn antenna. The work features experimental measurements over a wide frequency range of 0.5 to 1.5 GHz and a wide discharge with current values from 35 to 200 mA. The specific frequency band and uniquely selected geometry allowed for the investigation of both the in-phase and out-of-phase antenna modes, while some modes were found to have a narrow directional radiation pattern, within 50 degrees, with a beam width of −3 dB. The parameters of the gas-discharge plasma were also evaluated using drift theory, as well as using the microwave transmission of the 20 GHz signal. The electron density value corresponding to the used discharge currents was approximately from 4 × 10¹¹ to 7 × 10¹⁰ cm⁻³.

This paper has established a relatively comprehensive model for ultra-low frequency (ULF) current induced by thermal pressure gradients and its propagation. In the ULF current excitation model, we decomposed the current into a constant term unaffected by altitude and a product with a function significantly influenced by altitude. Combining this with the EISCAT background, we determined that for modulation frequencies below 5 Hz, the optimal height for ULF current excitation corresponds to the critical frequency height. We calculated the ionospheric currents at heating altitudes of 332 km for modulation frequencies of 5 Hz; the corresponding maximum currents were 1.03 × 10−10 A·m−2. By incorporating the current into the ULF waves propagation model based on magnetoionic theory, we found that the electromagnetic field energy is mainly concentrated in the horizontal direction, indicating that the energy primarily propagates outward through magnetosonic waves. The dominant components are the electric field component Ey and the magnetic field component Bz, whose maximum values reached 1.1 μV·m−1 and 1.5 pT. Unfortunately, magnetosonic waves cannot propagate downward due to the sharp variation in the real part of the refractive index between 200 and 300 km. However, the shear Alfvén waves component By can propagate downward, and there is still an intensity of approximately 0.1 pT at the bottom of the ionosphere, which is because the refractive index of shear Alfvén waves is most uniform in the parallel magnetic field direction, allowing By to propagate parallel to the magnetic field effectively.