In plasma kinetic theory, the Poisson-Vlasov model is incorporated to investigate the dispersion and damping rates of the dust-ion-acoustic waves (DIAWs) in hybrid, nonthermal, dusty plasmas. The ...longitudinal dielectric response function for DIAW in nonthermal dusty plasma having positively or negatively charged dust particles is obtained. In this way, more energetic particles (electrons) are modeled through nonthermal Vasyliunas-Cairns distributions while the ions and dust particles are kept Maxwellian. The effect of several parameters, such as electron-to-ion temperature ratio, dust concentration, and nonthermality parameters such as <inline-formula> <tex-math notation="LaTeX">\alpha </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">\kappa </tex-math></inline-formula>, are simultaneously investigated on the dispersion and damping rate of DIAWs. It is observed that both the real and imaginary frequencies of DIAWs are significantly influenced by the simultaneous presence of both nonthermality parameters. It is found that the presence of nonthermality parameters enhances DIAW wave frequency in positively or negatively dust charged case, whereas the Landau damping rate of the wave significantly decreases. The numerical plots are presented for illustration. This work is highly pertinent to the comprehensive picture of plasma mode analysis in nonthermal dusty plasmas.
The present article explores the effects of nonthermal nonextensive polarization force on nonlinear dust acoustic (DA) soliton and its energy. The nonthermal (or Cairns) polarization force (PF) ...acting on dust grains in a three-component unmagnetized dusty plasma is then revisited within the theoretical framework of the Tsallis statistical mechanics. Thus, a new PF expression is derived whose intensity <inline-formula> <tex-math notation="LaTeX">R</tex-math> </inline-formula> is sensibly affected and modified by the nonthermal nonextensive ions. Interestingly, we have shown that the nonextensivity makes the PF stronger while the nonthermality weakens it. Next, the principal modifications induced by Cairns-Tsallis PF on nonlinear DA solitons and its transported energy are investigated. In particular, we have found that for any value of nonextensive parameter <inline-formula> <tex-math notation="LaTeX">q</tex-math> </inline-formula>, the presence of Tsallis-Cairns PF makes the amplitude larger. Besides, we have remarked that when <inline-formula> <tex-math notation="LaTeX">R</tex-math> </inline-formula> increases (i.e., the magnitude of the PF approaches that of the electric force), the energy carried by the DA soliton undergoes depletion.
The Poison‐Vlasov model in plasma kinetic theory is taken into account to study the propagation of electron plasma waves (or Langmuir waves) in hot, un‐magnetized Vasyliunas‐Cairns distributed ...plasmas (VCDPs). The longitudinal dielectric plasma response function is obtained for such nonthermal plasmas. The Landau damping rate of Langmuir waves (LWs) in nonthermal VCDP, which propagates with a phase speed greater than the effective thermal speed of the electrons, is also studied. The real and imaginary parts of the wave frequency are investigated analytically as well as numerically and a comparison between the numerical and analytical results is presented. The finding reveals that the dispersion curve and damping rate of the wave are significantly influenced by the simultaneous presence of two nonthermality parameters, that is, ′α′ and ′κ′ (spectral index) in the hybrid (Vasyliunas‐Cairns) distributed plasmas. It is discussed that results are quite distinctive from that obtained in nonthermal plasmas that have sole presence of either of the nonthermality parameters ′α′ or super‐thermality spectral index ′κ′ in Cairns or kappa distributed electron plasmas, respectively. The more realistic form of 3D and reduced 1D distribution function of VCDP has been used to analyze LWs in describing nonthermal plasmas with more energetic electron in VCDP case.
Plain Language Summary
In this study, the kinetic theory is used to study wave propagation and damping rate of electron plasma (or Langmuir) waves in the hybrid nonthermal (containing the nonthermality parameters α and κ simultaneously). The Poison‐Vlasov model is described for studying LWs in VCDF plasmas. The presence of both nonthermality parameters α and κ have greatly influenced both the real and imaginary part of the frequencies of Langmuir waves (LWs) in comparison with earlier published work on the sole presence of anyone of the nonthermality parameter. It has been investigated that the presence of both these parameters has a significant effect of each other on both the dispersion curve and damping rates of LWs in VCDF plasmas. It is studied that the LWs are very high‐frequency waves and their resonance occurs at higher velocities and the damping rate of the electron plasma wave increases with the increase of nonthermality parameter α and decreases with the increase of nonthermality spectral index κ. This work opens the window of opportunities to understand various modes in space plasmas especially in the solar wind and heliospheric regions by the simultaneous fitting of nonthermal particles through the two important nonthermality parameters, that is, α and κ (spectral index).
Key Points
Simultaneous effect of nonthermality parameter and the spectral index has been studied on Langmuir waves
The dielectric function for the electrostatic waves using Kappa‐Cairns distribution has been derived
The results presented in this work are useful in the context of various space environments
The features of dust ion acoustic waves (DIAWs) composed of cold ions, nonthermal nonextensive electrons as well as stationary dust particles are presented by KP-type equations. The effect of system ...parameters and higher order contributions on the phase velocity, amplitude and width of DIAWs is discussed. The parametric range for the existence of negative and positive solitons described by KP equation is presented. It is found that nonthermal and nonextensivity parameters and higher order contribution play a very crucial role in the formation of DIAWs. The results obtained would be valuable in interpreting certain nonlinear physical phenomena presented in the Earth's magnetosphere.
This investigation presents the study of dust kinetic Alfvén wave solitons (DKAWSs) and quasi-periodic waves in a polarized dusty plasma comprising inertial dust, Cairns-Tsallis (CT) distributed ions ...and electrons. Using the reductive perturbation method, the KdV equation is derived and the Tanh-method is employed to derive its solution to study the dust kinetic Alfvén solitary structures. Furthermore, by considering the contribution of higher-order effects, the KdV-type inhomogeneous equation is derived and its solution results in the formation of dressed DKAWSs. The combined effects of polarization force and other plasma parameters on the characteristics of different kinds of DKAWSs are analyzed. Most importantly, from the conservation of KdV equations in the presence of external periodic perturbations, the study of quasi-periodic wave has also been illustrated. The analysis shows that the periodic solitonic behavior is transformed to quasi-periodic and also approaches chaotic oscillations. By changing different physical parameters, the numerical analysis of nonlinear DKAWs from periodic to quasi-periodic and to chaotic behavior has also been presented with external perturbation. The findings of this investigation are useful to understand the insight into physics of nonlinear phenomena for studying the dynamics of DKAWSs in space and astrophysical plasma environments.
Non-thermal plasma systems beyond the state of thermal equilibrium must have non-thermality dependent effective temperatures. These particle populations cannot have Maxwellian temperatures T∥,⊥e(M) ...which are typically considered at thermal equilibrium in the context of Maxwellian plasmas. Previously, in such dilute environments, numerous non-thermal distributions incorporating the concept of Maxwellian temperature T∥,⊥e(M) have been utilized, one of them is Cairns distribution (here termed as type-A). To ameliorate this inconsistency, we propose a more realistic form of Cairns distribution (type-B) with the vigorous definition of effective temperature and effective thermal velocity. Both Cairns distributions (A and B) are utilized to calculate the transverse dielectric response function (TDERF) of electromagnetic electron cyclotron (EMEC) mode. The exact numerical solution of TDERFs of EMEC instability reveals interesting and more promising repercussions in the case of Cairns-B i.e. an augmentation in the behavior of oscillatory and imaginary frequencies of the instability.
•Nonthermal populations beyond thermal equilibrium have effective temperatures.•Effective temperatures update plasma betas because of nonthermality dependence.•Cairns distribution shows an appreciable agreement with the observed distribution in solar wind.•Model-B style distributions better explain plasma dynamics, waves and instabilities.•Model-B explains natural rise in temperature due to increase in nonthermality in system.
The effect of trapped non-thermal polarization force on low-frequency solitary waves (dust acoustic solitons) is addressed in a collisionless complex plasma. For this purpose, we have firstly ...redefined the three-dimensional Cairns-Gurevich distribution that describes, simultaneously, the evolution of the energetic ions and those trapped in the plasma potential well, and derived the associated both density and polarization force expressions. The polarization force effects are remarkably modified due to the presence of the trapped non-thermal ions. In particular, we have found that the polarization force magnitude decreases with the increase of ion non-thermality character. Next, the modifications arising in dust-acoustic (DA) solitons and its energy due to the presence of these trapped non-thermal density and polarization force are analyzed. In particular, we have found that the presence of the polarization force leads to an increase in the amplitude and width of DA solitary wave can be propagated in different complex plasma media. Finally, a complementary study on the polarization force effects on the DA energy, associated with both space and experimental dusty plasmas, is also carried out. Our numerical results have shown that more is strong the polarization force more is higher the energy transported by DA solitons.
The dispersion properties and Landau damping rate of ion‐acoustic waves (IAWs) with the hybrid Cairns‐Tsallis distributed (CTD) electrons and Maxwellian ions are investigated using the plasma kinetic ...model based on Vlasov‐Poisson's equations. For both super‐extensive (q < 1) and sub‐extensive (q > 1) plasmas, the dielectric response function, real frequency, and Landau damping rate of IAWs are derived. By taking the effect of θi, e (ion‐to‐electron temperature ratio) into account, it is found that with the increase of ion temperature, the real frequency and wave dispersion effects increase as well (for both super‐extensive and sub‐extensive cases). Exploring the properties of the Landau damping rate of IAWs with the simultaneous presence of non‐thermal parameter α and non‐extensive parameter q, a comparison of numerical and analytical results is presented. It is found that in different ranges of θe, i (electron‐to‐ion temperature ratio), on decreasing the values of the non‐extensive parameter and increasing values of the non‐thermal parameter, the weak damping rate is observed (vice versa) in super‐extensive or super‐thermal plasma, although the trend of the damping rate in sub‐thermal plasma is similar (as in the case of super‐thermal plasma) but is less weak. It is further revealed that the damping rate of IAWs in thermal plasmas (Maxwellian) is stronger than the damping rate of IAWs in the case of non‐thermal plasmas (CTD). The current study is applicable to provide deep insight and further allow the exploration of electrostatic plasma modes in different space and laboratory plasma environments where the hybrid CTD plasma exists.
In this paper, the problem of large amplitude dust acoustic (DA) solitons has been addressed in a charge varying dusty plasma with ions following a Cairns‐Gurevich distribution. Based on the orbit ...motion limited approach, the correct Cairns‐Gurevich ion charging current is presented for the first time. The expression relating the variable dust charge to the plasma potential is given in terms of the Lambert function and we take advantage of this transcendental function to, carefully, analyse DA solitons in a charge varying dusty plasma with trapped nonthermal ions. Our results show that the spatial patterns of the variable charge solitary wave are significantly changed due to the presence of ion population modelled by the Cairns‐Gurevich distribution. An addition of a small concentration of trapped nonthermal ions makes the solitary structure less spiky, grows the net negative charge residing on the dust grain surface, and contributes to the electron depletion. Finally, our investigation is extended to highlight the effect of the grain dust charge variation. We have shown that under certain conditions, the impact of dust charge fluctuation may furnish an alternate physical mechanism rasing anomalous dissipation, which becomes more strong and may predominate over the dispersion as the nonthermal character of ions following the Cairns‐Gurevich distribution increases.
