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Electron holes (EH) are localized modes in plasma kinetic theory which appear as vortices in phase space. Earlier research on EH is based on the Schamel distribution function (df). A novel df is proposed here, generalizing the original Schamel df in a recursive manner. Nonlinear solutions obtained by kinetic simulations are presented, with velocities twice the electron thermal speed. Using 1D-1V kinetic simulations, their propagation characteristics are traced and their stability is established by studying their long-time evolution and their behavior through mutual collisions. [ABSTRACT FROM AUTHOR]

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 wavesThe dielectric function for the electrostatic waves using Kappa‐Cairns distribution has been derivedThe results presented in this work are useful in the context of various space environments [ABSTRACT FROM AUTHOR]

Recent experiments showed a decrease of long range correlations during the application of resonant magnetic perturbations (RMPs) [Y. Xu et al., Nucl. Fusion 51, 063020 (2011)]. This finding suggests that RMPs damp zonal flows. To elucidate the effect of the RMPs on zonal structures in drift wave turbulence, we construct a generalized Hasegawa-Wakatani model including RMP fields. The effect of the RMPs is to induce a linear coupling between the zonal electric field and the zonal density gradient, which drives the system to a state of electron radial force balance for large RMP amplitude. A predator-prey model coupling the primary drift wave dynamics to the zonal modes evolution is derived. This model has both turbulence drive and RMP amplitude as control parameters and predicts a novel type of transport bifurcation in the presence of RMPs. The novel regime has a power threshold which increases with RMP amplitude as γc~[δBrB]2.

In the published version of the paper we made a sign error in the calculation of the direction of the magnetic field in the rest frame of the particles, which affects the definition of the spin-up direction in the collision operators. Correcting this does not affect the main claims of the paper: (i) the reduction of the cascade growth rate, (ii) the polarization of high-energy particles being opposite to Sokolov–Ternov theory, and (iii) an excess or a shortage of particle production in the early stages of cascade development in photon seeded cascades depending on the photon polarization.

Kinetic theory and experimental observations of a special class of energetic particle driven instabilities called here beta-induced Alfv́n-acoustic eigenmodes (BAAEs) are reported confirming, previous results [N. N. Gorelenkov, Plasma Phys. Controlled Fusion 49, B371 (2007)]. The kinetic theory is based on the ballooning dispersion relation where the drift frequency effects are retained. BAAE gaps are recovered in kinetic theory. It is shown that the observed certain low-frequency instabilities on DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] and National Spherical Torus Experiment [M. Ono, S. M. Kaye, Y.-K. M. Peng, Nucl. Fusion 40, 557 (2000)] are consistent with their identification as BAAEs. BAAEs deteriorate the fast ion confinement in DIII-D and can have a similar effect in next-step fusion plasmas, especially if excited together with multiple global toroidicity-induced shear Alfv́n eigenmode instabilities. BAAEs can also be used to diagnose safety factor profiles, a technique known as magnetohydrodynamic spectroscopy. © 2009 American Institute of Physics.

Plasma kinetic theory predicts that sufficiently anisotropic proton distribution will excite electromagnetic ion cyclotron (EMIC) waves, which in turn relax the proton distribution to a marginally stable state creating an upper bound on the relaxed proton anisotropy. Here, using EMIC wave observations and coincident plasma measurements made by Van Allen Probes in the inner magnetosphere, we show that the proton distributions are well constrained by this instability to a marginally stable state. Near the threshold, the probability of EMIC wave occurrence is highest, having left‐handed polarization and observed near the magnetic equator with relatively small wave normal angles, indicating that these waves are locally generated. In addition, EMIC waves are distributed in two magnetic local time regions with different intensity. Compared with helium band waves, hydrogen band waves behave similarly except that they are often observed in low‐density regions. These results reveal several important features regarding EMIC waves excitation and propagation. Plain Language Summary: Electromagnetic ion cyclotron (EMIC) waves play a very important role in controlling plasma dynamics. In particular, EMIC wave‐particle interaction is a significant loss process for ring current ions and radiation belt relativistic electrons due to pitch angle scattering into the atmosphere. To understand the relationship between the generation of EMIC waves and the underlying plasma distributions, we perform a statistical survey to link the observed EMIC wave properties to the associated macroscopic state of the proton distributions by using 4 years of Van Allen Probe observations. We have found that close to the threshold of proton anisotropy instability, high occurrences of left‐hand polarized EMIC waves are usually observed near the magnetic equator with relatively small wave normal angles. In addition, there are two distinct magnetic local time regions of observed EMIC waves, with intense waves occurring on the duskside associated with high AE levels and relatively weak waves occurring in the noon sector accompanied by low AE levels. Furthermore, hydrogen band waves behave similarly to helium band waves except that these waves are often observed in low‐density regions while helium band waves are usually present in high‐density regions. These results provide important insights for studying the excitation mechanism of EMIC waves. Key Points: High occurrence of left‐handed waves is observed near equator with smaller WNA when close to the threshold of proton anisotropy instabilityEMIC waves are distributed in two MLT regions, with intense waves at the duskside and weak waves at the noon sectorH band waves behave similar to He band waves except that H band waves are usually present in low‐density regions [ABSTRACT FROM AUTHOR]

Basic kinetic process of plasmas is studied by a first principle based N-body simulation. By confirming Coulomb collisional relaxation process, this paper is extended to investigate the dynamics of Debye shielding. Some of the key numerical techniques are discussed, including how to avoid singularities at the near encounter of two charged particles. Electron distribution function in Debye shielding is revealed, which deviates from conventional Maxwellian distribution function. [ABSTRACT FROM AUTHOR]

Knowledge of dose linearity, plasma clearance, rate and extent of subcutaneous (SC) and intramuscular (IM) absorption of soluble aluminium (Al) citrate is considered a prerequisite for evaluation of toxicokinetic data obtained from SC or IM administration of Al adjuvants in medicinal products. Therefore, total Al plasma kinetics was investigated after SC, IM, and IV administration of single Al doses (36 and 360 µg/kg IM or SC; 30 and 300 µg/kg IV) given as citrate solution in rats. Control groups receiving vehicle (saline) were run in parallel to monitor background plasma Al levels over time resulting from dietary intake. Evaluation of Al plasma profiles was done by both non-compartmental analysis of baseline-corrected data and simultaneous model fitting to the raw data using a population kinetics approach. High and dose-independent total plasma clearance (6.6 mL/min/kg) was observed after IV administration corresponding to 60-82% of normal rat GFR. This supports the previous assumptions that parenterally administered Al citrate is more rapidly cleared from plasma than other Al species (e.g., chloride or lactate). Furthermore, plasma exposure of Al (Cmax and AUC0-inf) increased dose-proportionally at all administration routes. Fast and complete absorption of Al was observed at each dose level after both SC and IM administration (bioavailability estimates: 88 and 110%). Estimates for the first-order absorption rate constant ka correspond to absorption half-lives of 36 min (SC) and ≤ 13 min (IM). There was no increase in tissue Al content (whole bone and brain) after 36 µg/kg IM compared to control rats. [ABSTRACT FROM AUTHOR]

In this study, we investigate atmospheric microwave plasmas produced without electrodes while having a larger plasma volume in pure nitrogen. Optical emission spectroscopy is conducted to measure the translational, rotational, and vibrational temperatures of the plasma. Subsequently, three-temperature plasma kinetic simulations that consider the trans-rotational, vibrational, and electron temperatures separately are developed and conducted to study reaction pathways that sustain the plasma. The translational, rotational, and vibrational temperatures of the plasma are found to be the same and reach approximately 6000 K independent of the flow rate. In the plasma region, the molecular nitrogen is found to be dissociated into atoms to a significant extent because of the high gas temperature, and the plasma is sustained via associative ionizations rather than the electron-impact ionizations. [ABSTRACT FROM AUTHOR]

By taking the spin and polarization of the electrons, positrons and photons into account in the strong-field QED processes of nonlinear Compton emission and pair production, we find that the growth rate of QED cascades in ultra-intense laser fields can be substantially reduced. While this means that fewer particles are produced, we also found them to be highly polarized. We further find that the high-energy tail of the particle spectra is polarized opposite to that expected from Sokolov–Ternov theory, which cannot be explained by just taking into account spin-asymmetries in the pair production process, but results significantly from ‘spin-straggling’. We employ a kinetic equation approach for the electron, positron and photon distributions, each of them spin/polarization-resolved, with the QED effects of photon emission and pair production modelled by a spin/polarization dependent Boltzmann-type collision operator. For photon-seeded cascades, depending on the photon polarization, we find an excess or a shortage of particle production in the early stages of cascade development, which provides a path towards a controlled experiment. Throughout this paper we focus on rotating electric field configuration, which represent an idealized model and allows for a straightforward interpretation of the observed effects.

Using a kinetic theoretical approach, the characteristics of ion acoustic waves (IAWs) have been studied in a plasma whose electron and ion velocity distributions are modeled by a three dimensional q- nonextensive distribution function. It is found that the results of the one dimensional velocity distribution function are not accurate when compared to the results of three dimensional distribution function. Numerical solution of the dispersion relation for the ion acoustic wave has been obtained to study the effect of nonextensivity parameter q on the dispersion relation, the damping rate and the range of the values of the normalized wavenumber ( k λ D e ) for which the ion acoustic waves are weakly damped. It is also found that the change in the value of the electron nonextensivity parameter q e has a weak effect on the dispersion relation, the damping rate and the range of the values of the normalized wavenumber ( k λ D e ) for which the ion acoustic waves are weakly damped. However, change in the value of the ion nonextensivity parameter q i has very strong effect on the dispersion relation, the damping rate and the range of the values of the normalized wavenumber ( k λ D e ) for which the ion acoustic waves are weakly damped. [ABSTRACT FROM AUTHOR]

The auxiliary heating power absorption of 2.45 GHz and 4.6 GHz lower hybrid (LH) waves in EAST is analysed in order to improve the determination of the energy confinement time. The LH power absorption coefficient is obtained by using the time derivative of the total stored energy including the plasma kinetic energy and the poloidal magnetic field energy. Results on EAST have shown that, for both frequencies, the fraction of LH power absorbed in the plasma bulk decreases with the increase in the plasma density, and with the decrease in the toroidal magnetic field. Scaling laws for the density dependence of the LH absorption coefficient at different fields and frequencies have been statistically obtained. Comparison of the confinement improvement factor H89 obtained with these new scaling laws against those assuming an absorption coefficient equal to the launched k//wave spectrum directivity is made. [ABSTRACT FROM AUTHOR]

We study the process of magnetic reconnection in a coalescing magnetic island setup by means of numerical simulation. This process mimics flux tube merging which can take place in the solar corona, laboratory, and astrophysical objects. Simulations are performed with magnetohydrodynamics (MHD), Hall-MHD, and a newly developed Coupled MHD and Particle-In-Cell (PIC) model (CMAP). This model treats the global simulation domain with MHD, while the region around the reconnection zone is treated with PIC. This CMAP code allows us to simulate larger-scale domains with lesser computing power compared to fully PIC simulations. CMAP reproduces the dynamics of fully kinetic simulations which Hall-MHD does not capture, as seen in the Hall magnetic field and the reconnecting current sheet structure. For large islands in kinetic simulations, the current sheet does not form smoothly and shows chaotic behavior, and the magnetic islands also bounce and slosh. The current sheet thickness, length, and aspect ratios are calculated. They show that in the CMAP model, the thickness remains close to the ion skin depth, while the length changes weakly with the system size, giving a steady aspect ratio for the two largest system size simulations. The pressure tensor also shows large deviations from isotropy and gyrotropy near the current sheet. The CMAP simulations for smaller system sizes are compared to fully kinetic simulations, and we find that a minimum fraction of area has to be provided PIC feedback in the CMAP simulations in order to produce reconnection rates and dynamics similar to fully kinetic simulations. The reconnection rate reduces with the increasing island size. For the CMAP model, this reduction is steeper compared to MHD and Hall-MHD initially, but for larger system sizes, the reconnection rates in CMAP simulations show a steady behavior. [ABSTRACT FROM AUTHOR]

We demonstrate that the dragging of the magnetic field by the super-Alfvénic shear flows out of the reconnection plane can strongly localize the reconnection x-line in collisionless pair plasmas, reversing the current direction at the x-line. Reconnection with this new morphology, which is impossible in resistive-magnetohydrodynamics, is enabled by the particle inertia. Surprisingly, the quasi-steady reconnection rate remains of order 0.1 even though the aspect ratio of the local x-line geometry is larger than unity, which completely excludes the role of tearing physics. We explain this by examining the transport of the reconnected magnetic flux and the opening angle made by the upstream magnetic field, concluding that the reconnection rate is still limited by the constraint imposed at the inflow region. Based on these findings, we propose that this often observed fast rate value of order 0.1 itself, in general, is an upper bound value determined by the upstream constraint, independent of the localization mechanism and dissipation therein. [ABSTRACT FROM AUTHOR]

The main aim of the study was to establishin vivoa correlation between equol (EQU) production and a number of intestinal bacteria able to perform the transformation. Thus, healthy female volunteers were selected for their ability to convert slowly (n = 6, 105–109cells/g wet feces) or quickly (n = 6, 1010–1012cells/g wet feces) daidzein (DAI) in EQU. After oral administration of 100 mg DAI in soymilk, plasma (0–99 h) and urine (0–96 h) samples were collected. DAI and its metabolites were determined by LC-MS/MS and EQU -conjugates by UPLC-High Resolution-MS. Only for EQU a direct correlation was found between the number of transforming microorganisms and parameters such astmaxandt1/2(p = 0.027). Peak serum concentration time,Cmax, AUC0–72 handt1/2for total EQU (n = 12) were 36 ± 10 h, 89 ± 78 nM, 2.4 ± 1.7 (μmol × h/L) and 15.6 ± 3.3 h, respectively. In plasma and urine EQU was found mainly as 7-O-glucuronide. [ABSTRACT FROM PUBLISHER]

We report cross-sections and rate coefficients for excited states colliding with electrons, heavy particles and walls useful for the description of H2/He plasma kinetics under different conditions. In particular, the role of the rotational states in resonant vibrational excitations of the H2 molecule by electron impact and the calculation of the related cross-sections are illustrated. The theoretical determination of the cross-section for the rovibrational energy exchange and dissociation of H2 molecule, induced by He atom impact, by using the quasi-classical trajectory method is discussed. Recombination probabilities of H atoms on tungsten and graphite, relevant for the determination of the nascent vibrational distribution, are also presented. An example of a state-to-state plasma kinetic model for the description of shock waves operating in H2 and He-H2 mixtures is presented, emphasizing also the role of electronically-excited states in affecting the electron energy distribution function of free electrons. Finally, the thermodynamic properties and the electrical conductivity of non-ideal, high-density hydrogen plasma are finally discussed, in particular focusing on the pressure ionization phenomenon in high-pressure high-temperature plasmas. [ABSTRACT FROM AUTHOR]

This study is dedicated to the development of a multiscale approach for the simulation of silicon etching using the Bosch process. The etching simulator is composed of three modules: plasma kinetic model, sheath model, and surface model. The top down connection of these three modules allows us to track the etch profile evolution through the mask versus the reactor parameters. Complex reaction schemes are used for both SF6 and C4F8 plasmas to quantify the neutral and ion species densities and fluxes. For the SF6 plasma used in the etching cycle and in our pressure and power ranges, the fluorine flux is still preponderant compared to the positive ion flux, indicating that the silicon etching is mainly ensured by the chemical processes. For the C4F8 plasma used in the deposition cycle, the simulation results reveal that CFx species are preponderant in comparison with atomic fluorine, confirming that, in our operating conditions, CFx species promote the deposition of a polymer layer instead of the chemical etching by fluorine F. Plasma parameters in terms of the reactive neutral and ion fluxes and sheath parameters in terms of ion energy distribution functions are used in the surface model to track the etch profile evolution. The duty cycle corresponding to the SF6 to C4F8 plasma pulse ratio is a crucial parameter in controlling the Bosch process performances in terms of the etch rate, anisotropy, and scalloping defect development. A parametric study is performed to show the role of the duty cycle in the etch anisotropy and the scalloping propagation along the sidewall. While the scalloping defect is more important when the duty cycle is higher, the diminution of this parameter may reduce the global etch rate of silicon. [ABSTRACT FROM AUTHOR]

We compare, in an extensive and systematic way, linear theory results obtained with the hybrid (ion kinetic and electron fluid), the gyrokinetic and the fully kinetic plasma models. We present a test case with parameters that are relevant tor solar wind turbulence at small scales, which is a topic now recognized to need a kinetic treatment, to a certain extent. We comment on the comparison of low-frequency single modes (Alfven/ion-cyclotron, ion-acoustic and fast modes) for a wide range of propagation angles, and on the overall spectral properties of the linear operators, for quasi-perpendicular propagation. The methodology and the results presented in this paper will be valuable when choosing which model should be used in regimes where the assumptions of each model are not trivially satisfied. [ABSTRACT FROM AUTHOR]

In the present paper, the dispersions and Landau damping of the Langmuir waves and ion sound waves in the κ-deformed Kaniadakis distributed plasma system are investigated within the plasma kinetic theory regimes. The results show that the peculiarities of the dispersions and Landau damping of both the Langmuir waves and ion sound waves depend on the parameter κ of the distribution function. For Langmuir waves, the dispersion is enhanced, while the Landau damping is suppressed by κ. On the contrary, for ion sound waves, both the dispersion and Landau damping are increased by κ. As expected, the results of the Maxwellian case are recovered perfectly when κ = 0. [ABSTRACT FROM AUTHOR]

This paper formulates a fully general expression for spontaneously emitted electromagnetic fluctuations in magnetized thermal plasmas. The formulation is based upon the Klimontovich plasma kinetic theory. Specific application is made for high-frequency electromagnetic fluctuations in the upperhybrid and harmonic electron cyclotron frequency range. Potential application of the general formalism is discussed. [ABSTRACT FROM AUTHOR]

The paper provides a tutorial to the conceptual layout of a self-consistently coupled Particle-In-Cell/Test-Particle model for the kinetic simulation of sputtering transport in capacitively coupled plasmas at low gas pressures. It explains when a kinetic approach is needed and which numerical concepts allow for capturing the often observed nonequilibrium behavior of the charged and neutral particles. At the example of a generic sputtering discharge, both the fundamentals of the applied Monte Carlo methods as well as their conceptual details are elaborated on. Finally, two assumptions that are often exploited in the context of sputtering transport simulations, namely on the energy distribution of impinging ions as well as on the test particle approach, are validated for the proposed example discharge. [ABSTRACT FROM AUTHOR]

Recently, the plasma medicine received a lot of attention in the plasma and biology community. Most of the plasma treatment targets are living tissues and cells immersed in liquids (such as blood or culture media). Reactive species generated by plasma in the gas phase are transported into the liquid and possibly converted to different types of reactive species, so that they can affect tissues or cells. In this paper, we presented a numerical investigation of the interaction between the plasma and the cells immersed in the culture media. The space and time evolution of dissolved reactive species [reactive oxygen species (O2−, OH, H2O2, HO2, and O3) and reactive nitrogen species (O2NO−, NO, NO2−, NO3−, and O2NOH)] are studied by the mass balance model in liquid. The reaction mechanism and the effective transportation range of dissolved reactive species are analyzed. The pH of the liquid has significant effects on the concentration of O2−, HO2, O2NO−, and O2NOH in the culture media. The increasing concentration and the higher permittivity through the cell membrane of HO2 and O2NOH at acidic pH are consistent with higher bacterial inactivation efficiency of plasma treatment in acidic pH environment. The cellular and the subcellular concentration of HO2, O2NO−, and O2NOH are studied by the conservation equations in a spherically symmetric concentration field. The plasma treatment increased the cellular concentration of O2NO− over ten times. The HO2 generated by plasma aqueous species was the only way for superoxide to penetrate cell membrane and damage cytosolic fumarase B. The cellular plasma reactive species are also sensitive to the pH of culture media. [ABSTRACT FROM AUTHOR]

A simplified (7 species and 9 processes) plasma kinetic model is proposed to investigate the mechanism of the plasma aerodynamic actuation driven by nanosecond-pulsed dielectric barrier discharge (NS-DBD). The governing equations include conservation equations for each species, the Poisson equation for the electric potential, and Navier-Stokes equations for the gas dynamic flow. Numerical simulations of plasma discharge and flow actuation on NS-DBD plasma actuators have been carried out. Key discharge characteristics and the responses of the quiescent air were reproduced and compared to those obtained in experiments and numerical simulations. Results demonstrate that the reduced plasma kinetic model is able to capture the dominant species and reactions to predict the actuation in complicated hydrodynamics. For the one-dimensional planar and two-dimensional symmetric NS-DBD, the forming of the sheath collapse is mainly due to the charge accumulation and secondary emission from the grounded electrode. Rapid species number density rise and electric field drop occur at the edge of the plasma sheath, where the space charge density gradient peaks. For the aerodynamic actuation with typical asymmetry electrodes, discharge characteristics have a core area on the right edge of the upper electrode, where the value can be much higher. The formation and propagation of the compression waves generated through rapid heating have also been performed and compared to those measured in a recent experiment. Energy release leads to gas expansion and forms a cylindrical shock wave, centering at the upper electrode tip with low gas acceleration. For the present single pulsed 12 kV case, the mean temperature of gas heating reaches about 575 K at 1 μs and decreases to about 460 K at 10 μs. [ABSTRACT FROM AUTHOR]

A table of contents for the issue of "Contributions to Plasma Physics" journal is presented.

In this work, collisionless Landau fluid models are combined with collisional fluid models using a Padé approximation that is accurate in both collisionality limits. The collisionless models capture Landau damping through a nonlocal integro-differential sub-diffusion operator with ballistic characteristics. Collisional extensions of Landau fluid models are derived by analyzing the higher order moment equations which combine a Landau closure with collisional friction forces. The model derived here evolves fluid moments for density, parallel velocity, and anisotropic pressure and includes the frictional heat flux, the parallel thermal force and anisotropic electrical conductivity. Since anisotropies must vanish in the collisional limit, a simple closure can be derived if the friction force neglects pitch-angle scattering for the closure moments themselves. The resulting plasma physics model is potentially quite useful for applications in magnetic fusion and astrophysics. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The full- f gyrokinetic code ELMFIRE is used to simulate the impact of turbulent tokamak plasma transport on the edge plasma flow and scrape-off-layer width. The simulation is performed in the circular limiter configuration and extends from the magnetic axis to the material surface. The results show that the sheath potential and parallel Mach number are in agreement with theoretical predictions, while the E × B dynamics are strongly affected by the sheath boundary. The radial fall-off of density and temperature profiles show non-exponential behaviour in the scrape-off-layer. Numerical issues appearing in the ELMFIRE simulation of edge plasma transport are discussed. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The validity of modern gyrokinetic field theory is assessed for the tokamak edge. The basic structure of the Lagrangian and resulting equations and their conservation laws is reviewed. The conventional microturbulence ordering for expansion is small potential/arbitrary wavelength. The equilibrium ordering for expansion is long wavelength/arbitrary amplitude. The long-wavelength form of the conventional Lagrangian is derived in detail. The two Lagrangians are shown to match at long wavelength if the E × B Mach number is small enough for its corrections to the gyroaveraging to be neglected. Therefore, the conventional derivation and its Lagrangian can be used at all wavelengths if these conditions are satisfied. Additionally, dynamical compressibility of the magnetic field can be neglected if the plasma beta is small. This allows general use of a shear-Alfvén Lagrangian for edge turbulence and self consistent equilibrium-scale phenomena for flows, currents, and heat fluxes for conventional tokamaks without further modification by higher-order terms. Corrections in polarisation and toroidal angular momentum transport due to these higher-order terms for global edge turbulence computations are shown to be small. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

An energy-conserving reduced kinetic model is formulated which is valid for perturbations with large amplitude and long wavelength beyond the standard gyrokinetic ordering. The standard gyrokinetic model is elegantly formulated by the two-step phase space transformation consisting of the guiding-center and gyro-center transformations, but the amplitude of perturbations is assumed to be small in return for use of the two-step transformation. Besides, the wavelength of perturbations is assumed to be short in deriving the gyrokinetic Poisson equation. Both limitations are relaxed by using the modified guiding-center 1-form for flowing plasmas [Miyato et al., J. Phys. Soc. Jpn. 78, 104501 (2009)]. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Purpose: To compare the safety and efficacy of thulium laser enucleation of the prostate (ThuLEP) with plasmakinetic enucleation of the prostate (PKEP). Methods: A total of 127 patients with benign prostatic hyperplasia (BPH) were randomized to either ThuLEP ( n = 61) or PKEP ( n = 66). All patients were assessed preoperatively and followed up at 3, 6, and 12 months postoperatively. Baseline characteristics of the patients, perioperative data, postoperative outcomes, and complications were recorded. Results: The decrease in hemoglobin level and the catheter time were statistically significantly lower in the ThuLEP group compared with the PKEP group (0.80 ± 0.49 vs 0.99 ± 0.52, p = 0.037, and 1.85 ± 0.94 vs 2.28 ± 1.34, p = 0.042). There were no statistical differences in complications between the two groups ( p > 0.05). There was a significant improvement in 3, 6, and 12 months' parameters compared with preoperative values ( p < 0.001). Assessment at the 12-month follow-up showed no difference in urinary parameters between the two groups. Conclusions: ThuLEP and PKEP are both safe and efficient procedures for the treatment of patients with BPH. Compared with PKEP, ThuLEP provided less risk of hemorrhage and shorter catheter time, although the differences may be of little clinical relevance. Further well-designed trials with extended follow-up and larger sample size are needed to draw final conclusions about the efficacy of the two procedures. [ABSTRACT FROM AUTHOR]

Ivermectin (IVM) is probably one of the most widely used antiparasitic drugs worldwide, and its efficacy is well established. However, slight differences in formulation may change the plasma kinetics, the biodistribution, and in consequence, the efficacy of this compound. The present study focuses on the development of a novel nanocarrier for the delivery of lipophilic drugs such as IVM and its potential application in antiparasitic control. Lipid nanocapsules (LNC) were prepared by a new phase inversion procedure and characterized in terms of size, surface potential, encapsulation efficiency, and physical stability. A complement activation assay (CH50) and uptake experiments by THP-1 macrophage cells were used to assess the stealth properties of this nanocarrier in vitro. Finally, a pharmacokinetics and biodistribution study was carried out as a proof of concept after subcutaneous (SC) injection in a rat model. The final IVM-LNC suspension displayed a narrow size distribution and an encapsulation rate higher than 90 % constant over the evaluated time (60 days). Through flow cytometry and blood permanence measurements, it was possible to confirm the ability of these particles to avoid the macrophage uptake. Moreover, the systemic disposition of IVM in the LNC administered by the SC route was higher ( p < 0.05) (1367 ng h/ml) compared to treatment with a commercial formulation (CF) (1193 ng.h/ml), but no significant differences in the biodistribution pattern were found. In conclusion, this new carrier seems to be a promising therapeutic approach in antiparasitic control and to delay the appearance of resistance. [ABSTRACT FROM AUTHOR]

A nonthermal plasma reactor (NTPR) using two 2.45-GHz microwave (MW) generators for the abatement of nitrogen oxides (\text NO\text {x}) and sulfur (\text SO\text {x}) contained in the exhaust gas of a 200-kW marine diesel engine was built and tested. Numerical analysis based on a nonthermal plasma kinetics model for the abatement of \text NO\text{x} and \textSO\text{x} from marine diesel engine exhaust gas was performed. A generic kinetic model that implements electron collisions and plasma chemistry has been developed for applications involving low-temperature (50–100 K) nonthermal plasma. Abatement efficiencies of \text NO\text{x} and \text SO\text{x} were investigated for a range of mean electron energies, which directly impact on the rate constants of electron collisions. The simulation was conducted using the expected composition of exhaust gas from a typical two-stroke, slow-speed marine diesel engine. The simulation results predict that mean electron energy of 0.25–3.2 eV gives abatement efficiency of 99% for \text NO\text{x} and \text SO\text{x}. The minimum residence time required was found to be 80 ns for the mean electron energy of 1 eV. Multimode cavity was designed using COMSOL multiphysics. The NTPR performance in terms of \text NO\text{x} and \text SO\text{x} removal was experimentally tested using the exhaust from a 2-kW lab scale, two-stroke diesel engine. The experimental results also show that the complete removal of NO is possible with the MW plasma (yellow color) generated. However, it was found that generating required MW plasma is a challenging task and requires further investigation. [ABSTRACT FROM AUTHOR]

The linear stability of a magnetized plasma accompanying a temperature gradient is reexamined by using plasma kinetic theory. We propose that the anisotropic velocity distribution function should be decomposed into two components. One is proportional to the temperature gradient parallel to the background magnetic field. The other is proportional to the temperature gradient perpendicular to the background magnetic field. Since the amplitude of the anisotropic velocity distribution function is proportional to the heat conductivity, and the heat conductivity perpendicular to the magnetic field is strongly reduced, the first component of the anisotropic velocity distribution function is predominant. The anisotropic velocity distribution function induced by the temperature gradient along the background magnetic field drives plasma kinetic instability and circular polarized magnetic plasma waves are excited. We show that the instability is almost identical to the Weibel instability in the weakly magnetized plasma. However, in the case of the instability caused by the temperature gradient, whether wave vectors of modes are parallel to or antiparallel to the background magnetic field, the growth rate of one mode is suppressed and the growth rate of the other mode is enhanced due to the background magnetic field. In the strongly magnetized plasma, one mode is stabilized and only one of the modes remains unstable. The formulae for the jitter radiation spectrum emitted by relativistic electrons when they travel through the magnetized plasma with the plasma waves driven by the instability are deduced at the first time. We show that the synchrotron emission and the jitter radiation are simultaneously emitted from the same relativistic electron. The jitter radiation is expected to be circularly polarized but with a very small polarization degree since almost the same amounts of left-handed and right-handed circular polarized magnetic waves are excited by the instability. [ABSTRACT FROM AUTHOR]

The preferential ion orbit loss of counter-current directed ions leaves a predominantly co-current ion distribution in the thermalized ions flowing outward through the plasma edge of tokamak plasmas, constituting a co-current intrinsic rotation. A methodology for representing this essentially kinetic phenomenon in plasma fluid theory is described and combined with a previously developed methodology of treating ion orbit particle and energy losses in fluid theory to provide a complete treatment of ion orbit loss in plasma fluid rotation theory. [ABSTRACT FROM AUTHOR]

The hydrodynamics of a completely ionized two-component electron-ion plasma is investigated on the basis of the Landau kinetic equation with account for component temperature and velocity relaxation. The term relaxation is understood here in a narrow sense as a process which can take place in a spatially homogeneous system. The investigation is made on the basis of a generalized Chapman-Enskog method. The relaxation is investigated in the vicinity of the standard hydrodynamic state of plasma: the deviations of the component temperatures and velocities from their standard hydrodynamic values are considered to be small. The integral equations for the component distribution functions are investigated in a perturbation theory in small gradients and small relaxation parameters. The component distribution functions of the first-order both in gradients and in relaxation parameters are calculated. Relaxation corrections to the energy and momentum fluxes and to the kinetic coefficients of the standard hydrodynamic state of the system are obtained. [ABSTRACT FROM AUTHOR]

Description of a magnetized plasma involves the Vlasov equation supplemented with the non-linear Fokker–Planck collision operator. For non-Maxwellian distributions, the collision operator, however, is difficult to compute. In this Letter, we introduce Gaussian Radial Basis Functions (RBFs) to discretize the velocity space of the entire kinetic system, and give the corresponding analytical expressions for the Vlasov and collision operator. Outlining the general theory, we also highlight the connection to plasma fluid theories, and give 2D and 3D numerical solutions of the non-linear Fokker–Planck equation. Applications are anticipated in both astrophysical and laboratory plasmas. [ABSTRACT FROM AUTHOR]

Instead of the commonly used Vlasov equation, one is able to treat kinetic phenomena in collisionless plasma with the help of the infinite set of hydrodynamic equations. The present paper deals with the linear approximation of multiflow hydrodynamics. It is shown that single-particle and collective excitations analogous to Van Kampen waves are explicitly separated. Expressions for the energy of all eigenmodes are obtained. [ABSTRACT FROM AUTHOR]

Electron transport across a magnetic field in a magnetic-layer-type Hall thruster was numerically investigated for the future predictive modeling of Hall thrusters. The discharge of a 1-kW-class magnetic-layer-type Hall thruster designed for high-specific-impulse operation was modeled using an r-z two-dimensional fully kinetic particle code with and without artificial electron-diffusion models. The thruster performance results showed that both electron transport models captured the experimental result within discrepancies less than 20% in thrust and discharge current for all the simulated operation conditions. The electron cross-field transport mechanism of the so-called anomalous diffusion was self-consistently observed in the simulation without artificial diffusion models; the effective electron mobility was two orders of magnitude higher than the value obtained using the classical diffusion theory. To account for the self-consistently observed anomalous transport, the oscillation of plasma properties was speculated. It was suggested that the enhanced random-walk diffusion due to the velocity oscillation of low-frequency electron flow could explain the observed anomalous diffusion within an order of magnitude. The dominant oscillation mode of the electron flow velocity was found to be 20 kHz, which was coupled to electrostatic oscillation excited by global ionization instability. [ABSTRACT FROM AUTHOR]

In this work, we compare gyrokinetic (GK) with fully kinetic Particle-in-Cell (PIC) simulations of magnetic reconnection in the limit of strong guide field. In particular, we analyze the limits of applicability of the GK plasma model compared to a fully kinetic description of force free current sheets for finite guide fields (bg). Here, we report the first part of an extended comparison, focusing on the macroscopic effects of the electron flows. For a low beta plasma (βi=0.01), it is shown that both plasma models develop magnetic reconnection with similar features in the secondary magnetic islands if a sufficiently high guide field (bg≳30) is imposed in the kinetic PIC simulations. Outside of these regions, in the separatrices close to the X points, the convergence between both plasma descriptions is less restrictive (bg≳5). Kinetic PIC simulations using guide fields bg≲30 reveal secondary magnetic islands with a core magnetic field and less energetic flows inside of them in comparison to the GK or kinetic PIC runs with stronger guide fields. We find that these processes are mostly due to an initial shear flow absent in the GK initialization and negligible in the kinetic PIC high guide field regime, in addition to fast outflows on the order of the ion thermal speed that violate the GK ordering. Since secondary magnetic islands appear after the reconnection peak time, a kinetic PIC/GK comparison is more accurate in the linear phase of magnetic reconnection. For a high beta plasma (βi=1.0) where reconnection rates and fluctuations levels are reduced, similar processes happen in the secondary magnetic islands in the fully kinetic description, but requiring much lower guide fields (bg≲3). [ABSTRACT FROM AUTHOR]