This paper presents the results of an experimental study of inductive RF ion thruster prototype parameters, which have demonstrated a strong dependence of the prototype characteristics on the length of the gas-discharge chamber and the operational frequency of the RF generator. The best result was obtained when the prototype was operated at a frequency of 4 MHz with a gas-discharge chamber 5 cm long. The experiments demonstrated that there is a significant resource for improving thruster parameters associated with an increase in the fraction of the RF power absorbed by the plasma. The latter can be achieved by superimposing an external magnetic field on the discharge. In parallel with the results of the experiments, this paper presents numerical calculations based on the model taking into account the presence of a parasitic capacitive channel of the RF power input into the discharge, as well as power losses in the external circuit. Calculations have shown that the experimentally observed effects are associated with the effect of the capacitive RF power input channel, as well as the frequency dependence of the plasma's ability to absorb the RF power.

Present paper is aimed to reveal experimentally and theoretically the influence of magnetic field strength, antenna shape, pressure, operating frequency and geometrical size of plasma sources on the ability of plasma to absorb the RF power characterized by the equivalent plasma resistance for the case of low pressure RF inductive discharge located in the external magnetic field. The distinguishing feature of the present paper is the consideration of the antennas that generate not only current but charge on the external surface of plasma sources. It is shown that in the limited plasma source two linked waves can be excited. In case of antennas generating only azimuthal current the waves can be attributed as helicon and TG waves. In the case of an antenna with the longitudinal current there is a surface charge on the side surface of the plasma source, which gives rise to a significant increase of the longitudinal and radial components of the RF electric field as compared with the case of the azimuthal antenna current.

The measured dependences of the equivalent plasma resistance on the external magnetic field (0–50 G) in a 46-cm-diameter RF inductive plasma source operating at frequencies of 2, 4, and 13.56 MHz and a power of 100–500 W are presented. The experiments were carried out in argon at pressures of 0.1–30 mTorr. The presence of the external magnetic field leads to the appearance of resonance domains of efficient RF power absorption corresponding to the conditions of resonance excitation of helicons coupled with Trivelpiece–Gould modes. It is shown that RF power absorption at frequencies of 2 MHz can be optimized by applying an external magnetic field corresponding to the domains of resonance absorption. The effect is enhanced with increasing operating frequency.

The present paper deals with the experimental and numerical study of radio-frequency (RF) low-pressure discharge having both inductive and capacitive or DC channels. Two discharge schemes are considered. In the first case the inductive and capacitive channels are powered by two independent RF power sources. In the second case the inductor and capacitor plates, being the main parts of inductive and capacitive channels, are connected in parallel to one RF power source. The properties of the mentioned discharges are compared with that of pure inductive RF discharge. It is shown that the presence of the capacitive component leads to changes of the fraction of RF power coupled through the inductive channel. This manifests with a reduction of the RF source power value, at which the transition from E- to H-mode takes place, and with the disappearance of hysteresis.

This paper aims to analyze the mechanism of power absorption and to reveal, both experimentally and numerically, the basic factors determining the ability of plasma to absorb RF power. This is done by determining the plasma equivalent resistance value under different conditions in a low-pressure RF inductive discharge such as different antenna shape, working gas pressure, electron density, operating frequency and geometrical dimensions of the plasma source. Experimental and numerical results show that the plasma equivalent resistance changes non-monotonously with an increase in electron density, increases with an increase in neutral gas pressure, and that the maximum plasma equivalent resistance shifts toward higher electron densities when the operating frequency is increased.

The results from studying a dual-camera inductive radio-frequency (RF) discharge that was placed in an external magnetic field are presented. The operating conditions were as follows: an argon pressure of 5 × 10 –5 –6 × 10 –2 Torr, an external magnetic field strength of 0–60 G, and an RF generator power supply of 25–300 W. During the experiment the resonant RF power consumption and the correspondence between the local power-consumption maxima and spatial maxima of the plasma concentration as a function of the external magnetic field were observed. The comparison of the experimental results with the results of the mathematical simulation indicates that the resonant character of the discharge is associated with the excitation of helicons and Trivelpiece–Gould waves.

This paper presents the results of investigating the power absorption mechanism of an inductive RF discharge plasma. Dependences of the frequency of elastic electron collisions with inert gas atoms (helium, neon, argon, and krypton) on the pressure are given. In the frequency range of 3 × 106–3 × 107 s−1, an equivalent plasma resistance and the power input into the plasma are determined by the values of collision frequency and electron density within a skin layer and do not depend on the type of gas within the limits of experimental error. Upon reaching the electron temperature of ∼1 eV, the energy of the main part of electrons lies in the range of Ramsauer’s minimum for elastic cross section. This leads to a decreasing elastic-collision frequency in heavy inert gases as compared to helium.

This work is devoted to systematic investigation into the radial dependence of the plasma parameters of a low-pressure inductive radio-frequency (RF) discharge on pressure within a wide range of 0.8–1 Torr. Experimental results that were obtained under the considered pressures make it possible to analyze the patterns of the changes in plasma parameters upon both a nonlocal mode of discharge and a transition from a nonlocal to local mode of the RF power input. Discharges in helium, neon, argon, and krypton were considered. Experimental data were compared to the results of the numerical simulation of the inductive RF discharge using the particle-in-cell (PIC) method.

The paper presents the results of the authors many year work in the field of ion&plasma sources development. The families of DC and RF ion and plasma sources are described. The results of ion&plasma sources utilization in materials surface modification technologies are discussed.

The present paper deals with the experimental study of the RF power input mechanism to the plasma of RF hybrid discharge that is sustained by the RF power unit representing spiral antenna connected in parallel with the capacitor electrodes. At low values of RF generator power the RF power is shown to be coupled through capacitive channel of the discharge, later at higher values of RF generator power the role of inductive channel becomes more significant. The lower is the value of the disjunctive capacitor included to the capacitive channel the higher is the contribution of the inductive channel.