Generation of Short-scale Electrostatic Fields in the Solar Atmosphere and the Role of Helium Ions

Abstract Theoretical models are presented to show that expansion of plasma in the radial direction from a denser solar surface to a rarefied upper atmosphere with short-scale inhomogeneous field-aligned flows and currents in the form of thin threads itself is an important source of electrostatic instabilities. Multifluid theory shows that the shear flow–driven purely growing electric fields appear in the transition region. On the other hand, plasma kinetic theory predicts that the short-scale current sheets (or filaments) produce current-driven electrostatic ion acoustic (CDEIA) waves in the hydrogen plasma of the transition region that damp out in the system through wave–particle interactions and increase the temperature. Similar processes take place in the solar corona and act positively for increasing the temperature further and maintaining it. The shear flow–driven instabilities and CDEIA waves have short perpendicular wavelengths of the order of 1 m and low frequencies of the order of 1 or several Hz when the ions’ shear flow scale length is considered to be of the order of 1 km. It is pointed out that the purely growing fluid instabilities turn into oscillatory instabilities and the growth rates of kinetic CDEIA wave instabilities are reduced when the dynamics of 10% helium ions is taken into account along with 90% hydrogen ions. Therefore, the role of helium ions should not be ignored in the study of wave dynamics in solar plasma.

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The Role of Distress Disclosure Tendencies in the Experience and Expression of Laboratory-Induced Sadness

Journal of Individual Differences ◽

10.1027/1614-0001/a000222 ◽

2017 ◽

Vol 38 (1) ◽

pp. 55-62 ◽

Cited By ~ 1

Author(s):

Jeffrey H. Kahn ◽

Daniel W. Cox ◽

A. Myfanwy Bakker ◽

Julia I. O’Loughlin ◽

Agnieszka M. Kotlarczyk

Keyword(s):

Individual Differences ◽

Emotional Reactivity ◽

Subjective Experience ◽

Negative Emotion ◽

Theoretical Models ◽

Laboratory Research ◽

Emotion Words ◽

Distress Disclosure ◽

Computerized Text Analysis

Abstract. The benefits of talking with others about unpleasant emotions have been thoroughly investigated, but individual differences in distress disclosure tendencies have not been adequately integrated within theoretical models of emotion. The purpose of this laboratory research was to determine whether distress disclosure tendencies stem from differences in emotional reactivity or differences in emotion regulation. After completing measures of distress disclosure tendencies, social desirability, and positive and negative affect, 84 participants (74% women) were video recorded while viewing a sadness-inducing film clip. Participants completed post-film measures of affect and were then interviewed about their reactions to the film; these interviews were audio recorded for later coding and computerized text analysis. Distress disclosure tendencies were not predictive of the subjective experience of emotion, but they were positively related to facial expressions of sadness and happiness. Distress disclosure tendencies also predicted judges’ ratings of the verbal disclosure of emotion during the interview, but self-reported disclosure and use of positive and negative emotion words were not associated with distress disclosure tendencies. The authors present implications of this research for integrating individual differences in distress disclosure with models of emotion.

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Transport and fluctuations in nonlinear-dissipative systems: role of interparticle collisions

Nonlinear Analysis Modelling and Control ◽

10.15388/na.1999.4.0.15249 ◽

1999 ◽

Vol 4 ◽

pp. 31-86 ◽

Cited By ~ 1

Author(s):

R. Katilius ◽

A. Matulionis ◽

R. Raguotis ◽

I. Matulionienė

Keyword(s):

Electric Fields ◽

Carrier Density ◽

Experimental Results ◽

Dissipative Systems ◽

Doped Semiconductors ◽

Electron Diffusion ◽

Electron Collisions ◽

Electric Noise ◽

Diffusion Phenomena

The goal of the paper is to overview contemporary theoretical and experimental research of the microwave electric noise and fluctuations of hot carriers in semiconductors, revealing sensitivity of the noise spectra to non-linearity in the applied electric field strength and, especially, in the carrier density. During the last years, investigation of electronic noise and electron diffusion phenomena in doped semiconductors was in a rapid progress. By combining analytic and Monte Carlo methods as well as the available experimental results on noise, it became possible to obtain the electron diffusion coefficients in the range of electric fields where inter-electron collisions are important and Price’s relation is not necessarily valid. Correspondingly, a special attention to the role of inter-electron collisions and of the non-linearity in the carrier density while shaping electric noise and diffusion phenomena in the non-equilibrium states will be paid. The basic and up-to-date information will be presented on methods and advances in this contemporary field - the field in which methods of non-linear analytic and computational analysis are indispensable while seeking coherent understanding and interpretation of experimental results.

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Exploring the role of identity fusion and group identification in predicting parochialism amongst Indonesian Islamic groups

10.31234/osf.io/e8ytr ◽

2019 ◽

Author(s):

Christopher Michael Kavanagh ◽

Susilo Wibisono ◽

Rohan Kapitány ◽

Whinda Yustisia ◽

Idhamsyah Eka Putra ◽

...

Keyword(s):

Group Identification ◽

Control Sample ◽

Theoretical Models ◽

Religious Groups ◽

Diverse Range ◽

Beliefs And Practices ◽

Identity Fusion ◽

Beliefs And Practice ◽

Fusion Theory

Indonesia is the most populous Islamic country and as such is host to a diverse range of Islamic beliefs and practices. Here we examine how the diversity of beliefs and practices among Indonesian Muslims relates to group bonding and parochialism. In particular, we examine the predictive power of two distinct types of group alignment, group identification and identity fusion, among individuals from three Sunni politico-religious groups - a fundamentalist group (PKS), a moderate group (NU), and a control sample of politically unaffiliated citizens. Fundamentalists were more fused to targets than moderates or citizens, but contrary to fusion theory, we found across all groups, that group identification (not fusion) better predicted parochialism, including willingness to carry out extreme pro-group actions. We discuss how religious beliefs and practice impact parochial attitudes, as well as the implications for theoretical models linking fusion to extreme behaviour.

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Millimeter (MM) wave and microwave frequency radiation produce deeply penetrating effects: the biology and the physics

Reviews on Environmental Health ◽

10.1515/reveh-2020-0165 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Martin L. Pall

Keyword(s):

Magnetic Fields ◽

Electric Fields ◽

Cardiac Activity ◽

Maximum Level ◽

Voltage Sensor ◽

The Body ◽

Time Varying ◽

The Brain ◽

Mm Waves

Abstract Millimeter wave (MM-wave) electromagnetic fields (EMFs) are predicted to not produce penetrating effects in the body. The electric but not magnetic part of MM-EMFs are almost completely absorbed within the outer 1 mm of the body. Rodents are reported to have penetrating MM-wave impacts on the brain, the myocardium, liver, kidney and bone marrow. MM-waves produce electromagnetic sensitivity-like changes in rodent, frog and skate tissues. In humans, MM-waves have penetrating effects including impacts on the brain, producing EEG changes and other neurological/neuropsychiatric changes, increases in apparent electromagnetic hypersensitivity and produce changes on ulcers and cardiac activity. This review focuses on several issues required to understand penetrating effects of MM-waves and microwaves: 1. Electronically generated EMFs are coherent, producing much higher electrical and magnetic forces then do natural incoherent EMFs. 2. The fixed relationship between electrical and magnetic fields found in EMFs in a vacuum or highly permeable medium such as air, predicted by Maxwell’s equations, breaks down in other materials. Specifically, MM-wave electrical fields are almost completely absorbed in the outer 1 mm of the body due to the high dielectric constant of biological aqueous phases. However, the magnetic fields are very highly penetrating. 3. Time-varying magnetic fields have central roles in producing highly penetrating effects. The primary mechanism of EMF action is voltage-gated calcium channel (VGCC) activation with the EMFs acting via their forces on the voltage sensor, rather than by depolarization of the plasma membrane. Two distinct mechanisms, an indirect and a direct mechanism, are consistent with and predicted by the physics, to explain penetrating MM-wave VGCC activation via the voltage sensor. Time-varying coherent magnetic fields, as predicted by the Maxwell–Faraday version of Faraday’s law of induction, can put forces on ions dissolved in aqueous phases deep within the body, regenerating coherent electric fields which activate the VGCC voltage sensor. In addition, time-varying magnetic fields can directly put forces on the 20 charges in the VGCC voltage sensor. There are three very important findings here which are rarely recognized in the EMF scientific literature: coherence of electronically generated EMFs; the key role of time-varying magnetic fields in generating highly penetrating effects; the key role of both modulating and pure EMF pulses in greatly increasing very short term high level time-variation of magnetic and electric fields. It is probable that genuine safety guidelines must keep nanosecond timescale-variation of coherent electric and magnetic fields below some maximum level in order to produce genuine safety. These findings have important implications with regard to 5G radiation.

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Elucidating the Influence of Electric Fields toward CO2 Activation on YSZ (111)

Catalysts ◽

10.3390/catal11020271 ◽

2021 ◽

Vol 11 (2) ◽

pp. 271

Author(s):

Nisa Ulumuddin ◽

Fanglin Che ◽

Jung-Il Yang ◽

Su Ha ◽

Jean-Sabin McEwen

Keyword(s):

Electric Field ◽

Electric Fields ◽

Heterogeneous Catalysts ◽

Co2 Reduction ◽

Total Density ◽

Reverse Water Gas Shift ◽

High Thermodynamic Stability ◽

Shift Reaction ◽

Water Gas

Despite its high thermodynamic stability, the presence of a negative electric field is known to facilitate the activation of CO2 through electrostatic effects. To utilize electric fields for a reverse water gas shift reaction, it is critical to elucidate the role of an electric field on a catalyst surface toward activating a CO2 molecule. We conduct a first-principles study to gain an atomic and electronic description of adsorbed CO2 on YSZ (111) surfaces when external electric fields of +1 V/Å, 0 V/Å, and −1 V/Å are applied. We find that the application of an external electric field generally destabilizes oxide bonds, where the direction of the field affects the location of the most favorable oxygen vacancy. The direction of the field also drastically impacts how CO2 adsorbs on the surface. CO2 is bound by physisorption when a +1 V/Å field is applied, a similar interaction as to how it is adsorbed in the absence of a field. This interaction changes to chemisorption when the surface is exposed to a −1 V/Å field value, resulting in the formation of a CO3− complex. The strong interaction is reflected through a direct charge transfer and an orbital splitting within the Olatticep-states. While CO2 remains physisorbed when a +1 V/Å field value is applied, our total density of states analysis indicates that a positive field pulls the charge away from the adsorbate, resulting in a shift of its bonding and antibonding peaks to higher energies, allowing a stronger interaction with YSZ (111). Ultimately, the effect of an electric field toward CO2 adsorption is not negligible, and there is potential in utilizing electric fields to favor the thermodynamics of CO2 reduction on heterogeneous catalysts.

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Role of compatibilizer in multicomponent polymer mixtures under shear flow

Soft Matter ◽

10.1039/c2sm26342d ◽

2013 ◽

Vol 9 (1) ◽

pp. 255-260 ◽

Cited By ~ 6

Author(s):

Ruohai Guo ◽

Jialin Li ◽

Li-Tang Yan ◽

Xu-Ming Xie

Keyword(s):

Shear Flow ◽

Polymer Mixtures ◽

Multicomponent Polymer

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THE ROLE OF NEGATIVE ENERGY WAVES IN LINEAR AND NONLINEAR SHEAR-FLOW INSTABILITY IN HYPERELASTIC FLUID-FILLED TUBES

The Quarterly Journal of Mechanics and Applied Mathematics ◽

10.1093/qjmam/46.4.657 ◽

1993 ◽

Vol 46 (4) ◽

pp. 657-681 ◽

Cited By ~ 2

Author(s):

CARMEN B. ROPCHAN ◽

GORDON E. SWATERS

Keyword(s):

Shear Flow ◽

Flow Instability ◽

Negative Energy ◽

Linear And Nonlinear ◽

Nonlinear Shear ◽

Shear Flow Instability

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Numerical study of electric field effects on the deformation of two-dimensional liquid drops in simple shear flow at arbitrary Reynolds number

Journal of Fluid Mechanics ◽

10.1017/s0022112009006442 ◽

2009 ◽

Vol 626 ◽

pp. 367-393 ◽

Cited By ~ 32

Author(s):

STEFAN MÄHLMANN ◽

DEMETRIOS T. PAPAGEORGIOU

Keyword(s):

Steady State ◽

Shear Flow ◽

Electric Field ◽

Electric Fields ◽

Simple Shear ◽

Simple Shear Flow ◽

Physical Parameters ◽

Shear Stresses ◽

Two Dimensional ◽

Liquid Drops

The effect of an electric field on a periodic array of two-dimensional liquid drops suspended in simple shear flow is studied numerically. The shear is produced by moving the parallel walls of the channel containing the fluids at equal speeds but in opposite directions and an electric field is generated by imposing a constant voltage difference across the channel walls. The level set method is adapted to electrohydrodynamics problems that include a background flow in order to compute the effects of permittivity and conductivity differences between the two phases on the dynamics and drop configurations. The electric field introduces additional interfacial stresses at the drop interface and we perform extensive computations to assess the combined effects of electric fields, surface tension and inertia. Our computations for perfect dielectric systems indicate that the electric field increases the drop deformation to generate elongated drops at steady state, and at the same time alters the drop orientation by increasing alignment with the vertical, which is the direction of the underlying electric field. These phenomena are observed for a range of values of Reynolds and capillary numbers. Computations using the leaky dielectric model also indicate that for certain combinations of electric properties the drop can undergo enhanced alignment with the vertical or the horizontal, as compared to perfect dielectric systems. For cases of enhanced elongation and alignment with the vertical, the flow positions the droplets closer to the channel walls where they cause larger wall shear stresses. We also establish that a sufficiently strong electric field can be used to destabilize the flow in the sense that steady-state droplets that can exist in its absence for a set of physical parameters, become increasingly and indefinitely elongated until additional mechanisms can lead to rupture. It is suggested that electric fields can be used to enhance such phenomena.

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Electric potential differences across auroral generator interfaces

Annales Geophysicae ◽

10.5194/angeo-31-251-2013 ◽

2013 ◽

Vol 31 (2) ◽

pp. 251-261 ◽

Cited By ~ 11

Author(s):

J. De Keyser ◽

M. Echim

Keyword(s):

Electric Field ◽

High Altitude ◽

Electric Fields ◽

Electric Potential ◽

Equilibrium Configuration ◽

Potential Difference ◽

Field Profile ◽

Electric Potential Difference ◽

Electric Field Profile

Abstract. Strong localized high-altitude auroral electric fields, such as those observed by Cluster, are often associated with magnetospheric interfaces. The type of high-altitude electric field profile (monopolar, bipolar, or more complicated) depends on the properties of the plasmas on either side of the interface, as well as on the total electric potential difference across the structure. The present paper explores the role of this cross-field electric potential difference in the situation where the interface is a tangential discontinuity. A self-consistent Vlasov description is used to determine the equilibrium configuration for different values of the transverse potential difference. A major observation is that there exist limits to the potential difference, beyond which no equilibrium configuration of the interface can be sustained. It is further demonstrated how the plasma densities and temperatures affect the type of electric field profile in the transition, with monopolar electric fields appearing primarily when the temperature contrast is large. These findings strongly support the observed association of monopolar fields with the plasma sheet boundary. The role of shear flow tangent to the interface is also examined.

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