Thermal Electron Research Articles

Introduction to Faraday tomography and its future prospects

Abstract Faraday tomography is a new method of the study of cosmic magnetic fields enabled by broad-band low-frequency radio observations. Using Faraday tomography it is possible to obtain the Faraday dispersion function, which contains information on the line-of-sight distributions of magnetic fields, thermal electron density, and cosmic ray electron density by measuring the polarization spectrum from a source of synchrotron radiation over a wide band. Furthermore, by combining it with two-dimensional imaging, Faraday tomography allows us to explore the three-dimensional structure of polarization sources. Faraday tomography has been active over the last 20 years, since the broad-band observation has become technically feasible, and polarization sources such as interstellar space, supernova remnants, and galaxies have been investigated. However, the Faraday dispersion function is mathematically the Fourier transform of the polarization spectrum. And since the observable band is finite, it is impossible to obtain a complete Faraday dispersion function by performing a Fourier transform. For this purpose, various methods have been developed to accurately estimate the Faraday dispersion function from the observed polarization spectrum. In addition, the Faraday dispersion function does not directly reflect the distribution of magnetic field, thermal electron density, and cosmic ray electron density in the physical space, and its physical interpretation is not straightforward. Despite these two difficult problems, Faraday tomography is attracting much attention because it has great potential as a new method for studying cosmic magnetic fields and magnetized plasmas. In particular, the next-generation radio telescope SKA (Square Kilometre Array) is capable of polarization observation with unprecedented sensitivity and broad bands, and the application of Faraday tomography is expected to make dramatic progress in the field of cosmic magnetic fields. In this review, we explain the basics of Faraday tomography with simple and instructive examples. Representative algorithms to realize Faraday tomography are introduced, and some applications are shown.

Thermal Electron Heat Fluxes Associated With Precipitated Auroral Electrons During the Saint Patrick's Days 2013 and 2015 Geomagnetic Storms

AbstractThe Rice Convection Model‐Equilibrium (RCM‐E) and SuperThermal Electron Transport (STET) are combined to investigate electron heat flux formation in the region of the diffuse aurora for the geomagnetic storms of 17 March 2013 and 17 March 2015. The primary electron precipitation into the atmosphere resulting from wave particle scattering in the magnetosphere are simulated by the magnetically and electrically RCM‐E during these two geomagnetic storms. The primary precipitating electron fluxes are modified by the STET model by taking into account atmospheric backscatter processes. The modified electron energy fluxes and their mean energies are coupled to the STET code to calculate electron thermal fluxes associated with diffuse aurora on a global scale. We use the simulated heat flux to estimate electron temperatures at the upper ionospheric altitudes and compare them with corresponding observations from the Defense Meteorological Satellite Program satellite.

Retracted: New Types of Electron Pitch Angle Distributions on Mars: Funnel and Skirt Distributions

AbstractUsing high‐resolution Solar Wind Electron Analyzer data from the Mars Atmosphere and Volatile EvolutioN spacecraft, we report two new types of electron pitch angle distributions (PADs) in the Martian plasma environment. The first type of electron PADs, showing pitch angle primally around , is termed funnel distribution, which was observed near the terminator and at about 1,200 km altitude. The second type of electron PADs, showing pitch angle primally around , is termed skirt distribution, which was detected on the nightside and at about 1,250 km altitude. The electrons of funnel and skirt distributions do not exhibit any photoelectron signatures and are shown to originate from the solar wind. Through the fitting analysis, we find that the electrons showing both funnel and skirt PADs are thermal electron populations and suprathermal electron populations. In addition, the possibilities that such two types of electron pitch angle distributions corresponding to magnetic field configurations are also discussed.

Modelling kilonova afterglows: Effects of the thermal electron population and interaction with GRB outflows

AbstractGiven an increasing number of gamma-ray bursts accompanied by potential kilonovae, there is a growing importance to advance modelling of kilonova afterglows. In this work, we investigate how the presence of two electron populations that follow a Maxwellian (thermal) and a power-law (non-thermal) distribution affect kilonova afterglow light curves. We employ semi-analytic afterglow model, PyBlastAfterglow. We consider kilonova ejecta profiles from ab-initio numerical relativity binary neutron star merger simulations, targeted to GW170817. We do not perform model selection. We find that the emission from thermal electrons dominates at early times. If the interstellar medium density is high (${\simeq }0.1\, \, \text{cm}^{-3}$), it adds an early time peak to the light curve. As ejecta decelerates, the spectral and temporal indexes change in a characteristic way that, if observed, can be used to reconstruct the ejecta velocity distribution. For the low interstellar medium density, inferred for GRB 170817A, the emission from the non-thermal electron population generally dominates. We also assess how kilonova afterglow light curves change if the interstellar medium has been partially removed and pre-accelerated by laterally expanding gamma-ray burst ejecta. For the latter, we consider properties informed by observations of GRB170817A. We find that the main effect is the emission suppression at early time ${\lesssim }10^{3}\,$ days, and at its maximum it reaches ${\sim }40{{\ \rm per\ cent}}$ when the fast tail of the kilonova ejecta moves subsonically through the wake of laterally spreading gamma-ray burst ejecta. The subsequent rebrightening, when these ejecta break through and shocks form, is very mild (${\lesssim }10{{\ \rm per\ cent}}$) and may not be observable.

Role of hemp fiber addition on thermal stability, heat insulation, air permeability and cellular structural features of rigid polyurethane foam

In this current study, rigid polyurethane foams (RPUFs) composites were prepared using different percentage (3, 6, 9 and 12%) of the hemp fibers via one-shut one-step polymerization method. The influences of the hemp fiber addition on the RPUFs were investigated meticulously by means of Fourier-transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), thermal conductivity measurement and scanning electron microscopy (SEM) techniques by evaluating the alternations in the chemical structures of the component, thermal stability, apparent density, insulation performance and cellular topology of the produced samples. The structural analysis revealed that there existed the strong secondary chemical bonds between the functional groups belonging to the components and, depending on that, the improvement in the thermal stability of the foam samples was recorded accompanied by the formation of the better interfacial adhesion. Furthermore, thermal conductivity values of the hemp fiber-loaded RPUFs were observed to increase regularly with the increasing of the content level of the hemp fibers. This was explained by enhancement in the bulk phase conduction level depending of the apparent density rising, reduction in CO2 concentration inside cells as well as the formation of the distorted cellular structures. The obtained air permeability results displayed that the hemp fibers incorporated successfully with RPUF structure, which provides the occurrence of the novel micro barriers and pathways limiting the passage of the air throughout the matrix. The taken scanning electron microscopy images also indicated that the cellular morphology and dimensional stability of the produced foams affected negatively by the hemp fiber addition. At high contents, the wrinkled, non-uniform and irregular cellular structures were observed with ruptured and collapsed walls and struts.

Creep Properties of Cylinder Metal Rubber under Static Compression at Elevated Temperatures

In this study, the creep properties of cylindrical metal rubber (MR) specimen under static compression at elevated temperatures were investigated by a series of creep experiments. The cylindrical MR specimen has a good symmetrical property, and the mechanical properties are consistent in its different axial section. The failure determination parameters of MR under the coupling of thermal and mechanical static load of the forming direction were proposed in four aspects: the overall height, the average stiffness, the energy dissipation, and the variation of the loss factor. The variation patterns of the properties of the MR specimens were investigated with a static load at different temperatures for 324 h. The analytical equipment, including the simultaneous thermal analyzer (TGA/DSC), X-ray diffractometer (XRD), and scanning electron microscope (SEM), were used for material characterization and failure analysis. Based on the results, it is found that there are significant differences in the MR property variations subjected to creep tests at different elevated temperatures. The results indicated that an appropriate heat treatment for MR specimens would improve the creep resistance at elevated temperatures. In addition, the overall height and energy dissipation of the MR specimens were increased, and the average stiffness and the loss factor were decreased under the creep tests at 200 °C and 250 °C. However, under the creep tests at 25 °C, 300 °C, 350 °C, and 400 °C, the overall height, the energy dissipation and the loss factor were decreased, but the average stiffness was increased.

Probing Plasma Composition with the Next Generation Event Horizon Telescope (ngEHT)

We explore the plasma matter content in the innermost accretion disk/jet in M87* as relevant for an enthusiastic search for the signatures of anti-matter in the next generation of the Event Horizon Telescope (ngEHT). We model the impact of non-zero positron-to-electron ratio using different emission models, including a constant electron to magnetic pressure (constant βe model) with a population of non-thermal electrons as well as an R-beta model populated with thermal electrons. In the former case, we pick a semi-analytic fit to the force-free region of a general relativistic magnetohydrodynamic (GRMHD) simulation, while in the latter case, we analyze the GRMHD simulations directly. In both cases, positrons are being added at the post-processing level. We generate polarized images and spectra for some of these models and find out that at the radio frequencies, both of the linear and the circular polarizations are enhanced with every pair added. On the contrary, we show that, at higher frequencies, a substantial positron fraction washes out the circular polarization. We report strong degeneracies between different emission models and the positron fraction, though our non-thermal models show more sensitivities to the pair fraction than the thermal models. We conclude that a large theoretical image library is indeed required to fully understand the trends probed in this study, and to place them in the context of a large set of parameters which also affect polarimetric images, such as magnetic field strength, black hole spin, and detailed aspects of the electron temperature and the distribution function.

EDIG-CHANGES I: extended Hα emission from the extraplanar diffuse ionized gas (eDIG) around CHANG-ES galaxies

ABSTRACT The extraplanar diffuse ionized gas (eDIG) represents the cool/warm ionized gas reservoir around galaxies. We present spatial analysis of the Hα images of 22 nearby edge-on spiral galaxies taken with the Apache Point Observatory 3.5-m telescope (eDIG-CHANGES). We conduct an exponential fit to the vertical Hα intensity profiles of the galaxies, of which 16 can be decomposed into thin + thick disk components. The median value of the Hα scale height of the thick disk is $\langle h_{\rm H\alpha }\rangle =1.13\pm 0.14\rm ~kpc$. We further examine the dependence of hHα on the stellar mass, SFR, and SFR surface density (SFRSD) of the galaxies. We find a tight sublinear correlation between hHα and SFR, expressed in hHα ∝ SFRα, where α ≈ 0.29. Moreover, the offset of individual galaxies from the best-fit SFR-hHα relation, expressed in hHα/SFRα, shows significant anti-correlation with SFRSD. We further compare the vertical extension of the eDIG to multi-wavelength measurements of other CGM phases. We find the eDIG slightly more extended than the neutral gas. This indicates the existence of some extended ionizing sources, in addition to the leaking photons from the disk star formation regions. Most galaxies have an X-ray scale height smaller than Hα, suggesting the majority of the X-ray photons are actually from the thick disk instead of the extended CGM. hHα is comparable to the L-band radio continuum scale height. This indicates that the thermal and non-thermal electrons have similar spatial distributions, a natural result if both are transported outwards by a galactic wind. This further indicates the thermal gas, cosmic rays, and magnetic field may be close to energy equipartition.

Study of Explosion Characteristics and Mechanism of Sucrose Dust

In order to investigate the explosion mechanism of sucrose in the air atmosphere, the explosion intensity under different ignition delay times (IDT), powder input pressures (PIP), and concentrations were studied using a 20L-sphere. The sucrose particles were analyzed in a synchronized thermal analyzer (STA) and scanning electron microscope (SEM). The results are as follows: 1. The DSC curve has two endothermic peaks and one exothermic peak, respectively at T = 180.5 ℃, 510.2 ℃ and 582.6 ℃. 2. The explosion intensity varies with the experiment conditions. The maximum explosion pressure (Pmax) appears when IDT = 90 ms, PIP = 1.5 MPa and concentration = 625 g/m3. 3. The explosive mechanism is a homogeneous combustion mechanism based on particle surface pyrolysis and volatilization. Because of the decomposition, H2, CO, furfural, and other flammable gas-phase products are released, then surface burn appears, which leads to the crystal rupture on account of thermal imbalance, resulting in multiple flame points and a chain explosion. As the temperature of the 20L-sphere rises, more explosive products are released, which causes a rapidly expanding explosion and eventually forms the explosion. This paper can be used as a reference for the prevention of explosion accidents in sucrose production processing.

Water-Based Environmentally Friendly Pesticide Formulations Based on Cyclodextrin/Pesticide Loading System

Difenoconazole (DIF) is a representative variety of broad-spectrum triazole fungicides and liposoluble pesticides. However, the water solubility of DIF is so poor that its application is limited in plant protection. In addition, the conventional formulations of DIF always contain abundant organic solvents, which may cause pollution of the environment. In this study, two DIF/cyclodextrins (CDs) inclusion complexes (ICs) were successfully prepared, which were DIF/β-CD IC and DIF/hydroxypropyl-β-CD IC (DIF/HP-β-CD IC). The effect of cyclodextrins on the water solubility and the antifungal effect of liposoluble DIF pesticide were investigated. According to the phase solubility test, the molar ratio and apparent stability constant of ICs were obtained. Fourier transform infrared spectroscopy, thermal gravity analysis, X-ray diffraction and scanning electron microscopy were used systematically to characterize the formation and characteristics of ICs. The results noted that DIF successfully entered the cavities of two CDs. In addition, the antifungal effect test proved the better performance of DIF/HP-β-CD IC, which exceeded that of DIF emulsifiable concentrate. Therefore, our study provides informative direction for the intelligent use of liposoluble pesticides with cyclodextrins to develop water-based environmentally friendly formulations.

Design, preparation, and combustion performance of energetic catalysts based on transition metal ions (Cu2+, Co2+, Fe2+) and 3-aminofurazan-4-carboxylic acid.

Development of energetic catalysts with high energy density and strong catalytic activity has become the focus and frontier of research, which is expected to improve the combustion performance and ballistic properties of solid propellants. In this work, three energetic catalysts, M(H2O)4(AFCA)2·H2O (AFCA = 3-aminofurazan-4-carboxylic acid, M = Cu, Co, Fe), are designed and synthesized based on the coordination reaction of transition metal ions and the energetic ligand. The target products are characterized by single crystal X-ray diffraction, Fourier transform infrared spectroscopy, differential thermal analysis, optical microscopy, and scanning electron microscopy. The results reveal that Cu(H2O)4(AFCA)2·H2O crystallizes in the monoclinic space group, Dc = 1.918 g cm-3. Co(H2O)4(AFCA)2·H2O, and Fe(H2O)4(AFCA)2·H2O belong to orthorhombic space groups, their density is 1.886 g cm-3 and 1.856 g cm-3, respectively. In addition, the designed catalysts show higher catalytic activity than some reported catalysts such as Co(en)(H2BTI)2]2·en (H3BTI = 4,5-bis(1H-tetrazol-5-yl)-1H-imida-zole), Co-AzT (H2AzT = 5,5'-azotetrazole-1,1'-diol), and [Pb(BTF)(H2O)2]n (BTF = 4,4'-oxybis [3,3'-(1-hydroxy-tetrazolyl)]furazan) for the thermal decomposition of ammonium perchlorate (AP). The high-temperature decomposition peak temperatures of AP/Cu(H2O)4(AFCA)2·H2O, AP/Co(H2O)4(AFCA)2·H2O, and AP/Fe(H2O)4 (AFCA)2·H2O are decreased by 120.3 °C, 151.8 °C and 89.5 °C compared to the case of pure AP, while the heat release of them are increased by 768.8 J g-1, 780.5 J g-1, 750.9 J g-1, respectively. Moreover, the burning rates of solid propellants composed of AP/Cu(AFCA)2(H2O)4·H2O, AP/Co(AFCA)2(H2O)4·H2O and AP/Fe(AFCA)2(H2O)4·H2O are increased by 2.16 mm s-1, 2.53 mm s-1, and 1.57 mm s-1 compared with the case of pure AP. This research shows considerable application prospects in improving the combustion and energy performance of solid propellants, it is also a reference for the design and preparation of other novel energetic catalysts.

Electron density effect of aromatic carboxylic acids in naphthalenediimide-based coordination polymers: from thermal electron transfer and charge transfer to photoinduced electron transfer.

Various naphthalenediimide (NDI) based electron donor-acceptor coordination polymers (D-A CPs) have been constructed and used to explore charge transfer (CT) and electron transfer (ET) behaviors. Up to now, significant progress has been made in the interface contact and electron donor-acceptor ability matching mechanism, while the electronic density effect of the electron donors on the CT and ET behaviors is still not known. Herein, two NDI-based D-A CPs, [Cd2(H2NDI)(IPA)2(H2O)2] (1) and [Cd2(H2NDI)(IPA-OH)2(H2O)2] (2), are constructed using an NDI-based ligand and two aromatic carboxylic acid ligands (H2NDI = 2,7-bis(3,5-dimethyl) dipyrazol-1,4,5,8-naphthalene tetracarboxydiimide, H2IPA = isophthalic acid; and H2IPA-OH = 5-hydroxyisophthalic acid). UV-vis and EPR spectroscopy and DFT calculations analyses reveal that the occurrence of themal electron transfer (TET) in 1 and 2 results from the HOMO of the IPA and IPA-OH lying higher than the LUMO of the NDI. Meanwhile, compared to 1, the UV-vis absorption spectrum of 2 exhibits a significant red shift, which suggests higher electron density of the donor and more electron transfer pathways are beneficial for the occurrence of intermolecular CT. After UV light irradiation, the comparison of the photochromic behavior of 1 and 2 confirms the negative effect of the stronger CT on photoinduced electron transfer (PET). The present study illustrates the delicate modulating effect of electron density on the CT and ET behaviors in D-A CPs.

Эталонное моделирование как метод решения нелинейных задач

In this paper, the method of reference modeling is considered, designed for calculation, analysis and mathematical modeling of nonlinear physical phenomena and technological processes. The advantages of this method, the possibility of its application in the entire range of basic parameters of a nonlinear problem, the uniformity of the design scheme for all types of problems are formulated. The proposed method is used to create models of convective diffusion in an inhomogeneous medium, scattering of thermal electrons in a field with central symmetry, and the behavior of electrical conductivity depending on temperature and dielectric permittivity of wide-band semiconductors. The problem of calculating the transparency of a potential barrier that a particle hits, considered as a test, gave a good result (an error in the range of 0.8-1.2%). In this paper, the main features of using the reference modeling method for solving nonlinear differential equations are demonstrated. The obtained results of analysis and modeling allow us to confidently assess the reliability of the general ideas of the reference modeling method, its design scheme, as well as the convergence of its decompositions, the similarity criteria of the system under study and the selected model. The method proposed in this paper, taking into account its approbation in various conditions, can serve as a basis for application in the study of nonlinear problems of various nature, finding approximate solutions to nonlinear differential equations.

Target polarization effect on energy loss of O<sup>5+</sup> ions near Bohr velocity in low density hydrogen plasma

Energy loss of ions near the Bohr velocity in plasma is one of the important topics in intense heavy ion beam driven high energy density physics and inertial confinement fusion. Based on the ions-plasma interaction experimental platform at HIRFL, this work shows the new experimental energy loss results of 1.07 MeV (~66.9 keV/u) O<sup>5+</sup> ions penetrating through a low-density partially ionized hydrogen plasma target (radio frequency plasma). The decrease of energy loss with free electron density increasing is found, which is very different from our previous result. The new experimental results are discussed by considering the theoretical models which involves the charge screening of projectiles in the partially ionized plasma and the target polarization effect-Barkas correction term. For the charge screening , the comparison between the momentum transfer under the Coulomb potential and that under the Debye potential is given, but due to the low ionization degree, the plasma screening effect seems not to be the main reason for the decrease of energy loss. For the target polarization effect , in the Bohr velocity regime, the Barkas correction term can play a key role in the ion-atom collisions. Modeling the Barkas correction term based on the proposed classical energy loss formula, the experimental data of ions in the gas target can be well fitted by the calculated values. In the partially ionized plasma, the frequent thermal electron collisions can give rise to the atomic excitation of plasma target, correspondingly the Barkas correction term changes: it decreases with the fraction of excited atoms increasing. As a result, the energy loss decreases in our experiment. In the stopping of highly charged ions in a partially ionized low-density plasma, the collisions between ions and free electrons can produce an enhanced energy loss according to previous studies. However, the target polarization effect, especially the atomic excitations, can significantly reduce the energy loss, which is observed in our experiment. Therefore, the interaction between ions and partially ionized plasma should be further studied, and the Barkas correction can be a very important term.

Photoelectrochemical reduction of CO2 catalyzed by a 3D core–shell NiMoO4@ZnO heterojunction with bicentre at the (111) plane and thermal electron assistance

The new mechanism of PEC reduction of CO2 on the bicentric catalyst is proven by DFT calculations and verified by the operando FTIR spectra, in which, the important intermediate of *OCH2 could connect each other for C2 products.

Electronic coupling and electron transfer in hydrogen-bonded mixed-valence compounds.

Electron transfer provided by hydrogen bonds represents a unique and highly significant area of research, as it has a crucial role to play in a wide variety of chemical and biological systems. The hydrogen-bonded mixed-valence system, in the form of donor-hydrogen bond-acceptor, provides an ideal platform for exploring thermally-induced electron transfer across this non-covalent unit. Over the past decades, ongoing progress has been made in this field. Here we critically assess some studies on the qualitative and quantitative evaluation of electronic coupling and thermal electron transfer across hydrogen bond interface. Additionally, selected experimental examples are discussed in terms of intervalence charge transfer, with particular attention paid to the proton-coupled and often overlooked proton-uncoupled electron transfer pathway in hydrogen-bonded mixed-valence systems. We further highlight the major limitations of this research area and suggest potential directions for future exploration.

Voltage waveform tailoring for high aspect ratio plasma etching of SiO2 using Ar/CF4/O2 mixtures: Consequences of ion and electron distributions on etch profiles

The quality of high aspect ratio (HAR) features etched into dielectrics for microelectronics fabrication using halogen containing low temperature plasmas strongly depends on the energy and angular distribution of the incident ions (IEAD) onto the wafer, as well as potentially that of the electrons (EEAD). Positive ions, accelerated to high energies by the sheath electric field, have narrow angular spreads and can penetrate deeply into HAR features. Electrons typically arrive at the wafer with nearly thermal energy and isotropic angular distributions and so do not directly penetrate deeply into features. These differences can lead to positive charging of the insides of the features that can slow etching rates and produce geometric defects such as twisting. In this work, we computationally investigated the plasma etching of HAR features into SiO2 using tailored voltage waveforms in a geometrically asymmetric capacitively coupled plasma sustained in an Ar/CF4/O2 mixture at 40 mTorr. The tailored waveform consisted of a sinusoidal wave and its higher harmonics with a fundamental frequency of 1 MHz. We found that some degree of control of the IEADs and EEADs is possible by adjusting the phase of higher harmonics φ through the resulting generation of electrical asymmetry and electric field reversal. However, the IEADs and EEADs cannot easily be separately controlled. The control of IEADs and EEADs is inherently linked. The highest quality feature was obtained with a phase angle φ = 0° as this value generated the largest (most negative) DC self-bias and largest electric field reversal for accelerating electrons into the feature. That said, the consequences of voltage waveform tailoring (VWT) on etched features are dominated by the change in the IEADs. Although VWT does produce EEADs with higher energy and narrower angular spread, the effect of these electrons on the feature compared to thermal electrons is not large. This smaller impact of VWT produced EEADs is attributed to thermal electrons being accelerated into the feature by electric fields produced by the positive in-feature charging.

Controllable synthesis of SrO-B2O3-SiO2-TiO2 glass-ceramics: Insight into the crystallization kinetics and dielectric properties

SrO-B2O3-SiO2-TiO2 (SBST) glass and glass-ceramics were prepared using the melt-quenching process with controlled crystallization kinetics. The influence of the Sr/Ti ratio on the structure, crystallization kinetics, and dielectric characteristics of SBST glass and glass-ceramics was investigated in detail. The samples were characterized using Raman spectroscopy, XPS spectroscopy, differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscope (SEM). The results indicate that a defined glass transition peak and two crystallization peaks were observed in the DTA curves of the SBST glass. The crystallization mechanisms of the two peaks were nucleation occurred on both the surface and inner phase. Most importantly, the SBST glass-ceramics showed excellent frequency and temperature stability, and especially SBST-1.10 glass-ceramics samples had dielectric losses as low as 1.07 × 10−3 (100 kHz, room temperature) and had excellent temperature stability (Δεr/εr298K < 10%) in the 298–500 K temperature range.

Quantum Chemical Calculations of 3-Benzyl-4-(3-Ethoxy-2-(4-Toluenesulfonlyoxy)-Benzlyideneamino]-4,5-Dihydro-1H-1,2,4-Triazol-5-One

In this study, 3-Benzyl-4-(3-ethoxy-2-(4-toluenesulfonlyoxy)-benzlyideneamino]-4,5-dihydro-1H-1,2,4-triazol-5-one was theoretically investigated. Initialy, the molecule was optimized by using DFT(B3LYP)/6-31G(d, p) basis set. The molecule’s structural parameters (dihedral angles, bond lengths and bond angles), HOMO (the highest occupied molecular orbital) and LUMO (the lowest unoccupied molecular orbital) energies, vibrational frequencies, thermodynamic and electronic properties (thermal capacity , rotation constants, entropy , total energy, electronegativity, electron affinity, chemical softness and hardness), the energy gap (ΔEgap = ELUMO-EHOMO), mulliken atomic charges, the surface maps were calculated by using Gaussian09W program. 13C- NMR and 1H-NMR chemical shift values of molecule also were calculated by GIAO. In additon, theoretical infrared (IR) vibration frequencies values which were scaled with certain scala factor were obtained using the veda4f program. Infrared spectra of molecul were formed according to obtained these values. The all spectroscopic and structural data of compounds were calculated by using 6-31G(d, p) basis set with density functional method (DFT/B3LYP) and compared with experimental values.

Nonlinear saturation of reverse shear Alfvén eigenmodes induced by kinetic electrons

A strong nonlinear saturation mechanism of the reverse shear Alfvén eigenmode (RSAE) induced by thermal electrons is observed in gyrokinetic particle-in-cell simulation. This nonlinear effect occurs at moderate mode amplitude, , and is associated with the electron parallel streaming along the perturbed magnetic field lines, the term , in the electron drift-kinetic equation. In the case of an n = 4 RSAE, where n is the toroidal mode number, this magnetic fluttering nonlinearity leads to strong mode coupling and broadening of the saturation spectrum. The nonlinear components, which are highly damped through the interaction between thermal electrons and the parallel electric field, modifies the RSAE mode structure and suppresses energetic particle drive significantly. The split-weight scheme (Chen and Parker 2007 J. Comput. Phys. 220 839–55) is used to simulate kinetic electrons.