Radial structure of low pressure rf capacitive discharges

Abstract

a b s t r a c tThis paper studies the glow intensity distribution of the discharge plasma against the tube radius and reports the radial profiles of electron temperature and plasma concentration in the rf capacitive discharge registered with a Langmuir probe. An abrupt increase of electron temperature and glow intensity near the tube wall in the weak-current a-mode of the rf capacitive discharge is revealed, the radial distribution of plasma concentration and ion flow to the electrodes possessing a maximum near the radial sheath boundary. In the g-mode of the rf capacitive discharge the electron temperature decrease in the total plasma volume leads to an electric field weakening and the peak of the glow intensity near the tube wall vanishes. The radial sheath thickness in the a-mode of the rf capacitive discharge obtained with 2D simulation experiences pulsations during the rf field period, the changing radial electric field heating electrons and increasing the plasma concentration near the boundary of the radial sheath.

Numerical simulation of an RF asymmetric nonthermal plasma reactor used for plasma polymerisation

“…A good agreement is observed between calculated results and the experimental results registered with a Langmuir probe from the literature [2] for the two-discharge mode.…”

“…The coupling with the external circuit is realized through a blocking capacity CB=100pF. First, a symmetric discharge chamber of 0.1m in diameter with a gap between flat parallel stainless-steel electrodes of L=0.022m is performed [2]. Then, an asymmetric electrodes simulation with anode diameter (0.10m), cathode diameter (0.12m) and gap between flat parallel stainless-steel electrodes (0.0254) is realized.…”

Implicit and electrostatic particle-in-cell/Monte Carlo model in two-dimensional and axisymmetric geometry: I. Analysis of numerical techniques

“…Since the computational costs are very high, most PIC/MC simulations were only done in 1D geometry up to now. Conventional 2D or 3D simulations are only possible for some cases where the densities are relatively low [14,16,17]. For most higher density cases in CCP, PIC/MC simulations of practical interesting systems often run on supercomputers [15,16,18].…”

Synthesis of Nanoparticles and Theoretical Model of Their Retention in Plasma of RF Capacitive Discharge with Vertically Arranged Electrodes in Acetylene

“…The main difference between the cases of horizontal and vertical electrodes is that the voltage drop in the near-electrode sheath (its constant component) can reach hundreds and even thousands of volts, ,, while the dielectric walls of the discharge tube are under a floating potential relative to the plasma, the sign of which is usually negative, and the value is usually 3–5 electron temperatures and does not exceed 15–20 V. , Consequently, only relatively small NPs can be retained in the discharge plasma with vertically arranged electrodes (in the experiments described above, we saw particles with a typical diameter of up to about 400–600 nm), while larger particles must overcome a small electric field force and fall onto the tube wall. With horizontal electrodes, gravity is opposed by a much stronger electric field in the near-electrode sheath, and much larger particles can be retained.…”