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Electrostatics, Electrodynamics and Fluid Mechanics of Plasma
Published in Alexander Fridman, Lawrence A. Kennedy, Plasma Physics and Engineering, 2021
Alexander Fridman, Lawrence A. Kennedy
The Stepwise Ionization Instability. This instability is similar to the fast ionization instability related to vibrational excitation, see 6.3.5. Here also the increase of electron concentration leads to additional population of excited species (but in this case electronically excited particles), which provides faster ionization and a further increase of electron concentration. The increment of this instability is approximately the frequency of electronic excitation. In contrast to the instability related to vibrational excitation (Section 6.3.5), this one cannot be as effectively stabilized by chemical reactions.
Characteristics of nonlinear ion-acoustic waves in collisional plasmas with ionization effects
Published in Waves in Random and Complex Media, 2022
However, all these investigations were confined to a model of IA waves without ionization. Due to the importance of the ionization effects in plasmas, many researchers have attempted to analyze the wave dynamics in the presence of ionization. The nonlinear aspects of dust ion-acoustic (DIA) waves with trapped electrons were investigated in Ref. [53] by considering ionization effects. They found that the amplitude of DIA waves decreases with the ionization and the ion recombination frequencies. Also, the nonlinear features of DIA waves in a dusty plasma in the presence of ionization, ion-dust, and ion-neutral collisions were studied by Ghosh [54]. A nonlinear K-dV like equation with a positive or negative damping term was found in this study. It is observed that by ionization instability, the amplitude of the DIA solitary waves grows exponentially with time, whereas ion-dust and ion-neutral collisions reduce this growth rate. In addition, the collisional and ionization effects on DIA solitary wave structures in a dusty plasma consisting of warm positive ions, warm negatively charged dust fluid, and two-temperature trapped electrons were considered in Ref. [55]. Shalaby et al. [56] investigated the characteristics of DIA solitary waves in collisional dusty plasmas with ionization effects. Using standard reductive perturbation theory, a damped Korteweg-de Vries (dK-dV) equation was derived. They displayed that DIA solitary waves with positive and negative potential can be propagated in this model. Also, they found that the amplitude decays (grows) with time when the collisional (ionization) effects dominate over the ionization (collisional) effects.
A multi-order nonlinear meta-analysis of bifluidic fireball sheath fluctuations
Published in Waves in Random and Complex Media, 2023
Subham Dutta, Pralay Kumar Karmakar
It is well-known that the plasma fireball (both direct and inverted) is purely a glow-discharge phenomenon irrespective of spatiotemporal scales [5]. The fireball glow is attributable to the spectral energy release of the excited neutrals in the plasma sheath. The neutral excitation occurs due to their collision (inelastic) with the rapidly drifting constitutive charged particles (electrons and ions) in response to the strong electric field associated with the surrounding double layer (DL) [5]. The DL volumetrically encompasses both the plasma sheath and the fireball with a strong electric field developed across it [1,6]. The electric field within the DL is induced because of the accumulation of opposite charges across its two edge layers [6]. It is noteworthy that both the sheath and DL are hosts of numerous nonlinear instabilities and other phenomena in the plasma fireball system, such as secondary ionization instability, electron transit time instability [7], Rayleigh-Taylor instability (RTI) [8], etc. The free energy for the eruption of the RTI in the PFS system originates from the stiff equilibrium charge density gradient across it. The resultant density gradient is a consequence of the un-even electric field strength across the sheath [8]. In other words, one may speculate that the PFS instability source is seeded in the existence of the zeroth-order non-zero plasma currents in the system. As a consequence of such free energies and hence, associated instabilities, there exist an extensive plethora of collective wave phenomena with diversified utilities in multiscale domains in different orders [3]. However, it is hereby seen that the instability dynamics of PFS, particularly on the nonlinear multi-order parametric regime, has still been lying as an open challenge yet to perceive for years [2]. Thus, the main motivation of the proposed study founded on the nonlinear multi-order PFS fluctuation dynamics of practical value and subsequent eigen-pattern analyses.