scholarly journals Role of Parallel Solenoidal Electric Field on Energy Conversion in 2.5D Decaying Turbulence with a Guide Magnetic Field

2021 ◽  
Vol 923 (2) ◽  
pp. 182
Author(s):  
Peera Pongkitiwanichakul ◽  
David Ruffolo ◽  
Fan Guo ◽  
Senbei Du ◽  
Piyawat Suetrong ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Energy Transfer ◽  
Kinetic Energy ◽  
Electric Field ◽  
Electromagnetic Energy ◽  
Plasma Kinetic ◽  
Background Magnetic Field ◽  
Out Of Plane ◽  
Decaying Turbulence ◽  
Guide Magnetic Field

Abstract We perform 2.5D particle-in-cell simulations of decaying turbulence in the presence of a guide (out-of-plane) background magnetic field. The fluctuating magnetic field initially consists of Fourier modes at low wavenumbers (long wavelengths). With time, the electromagnetic energy is converted to plasma kinetic energy (bulk flow+thermal energy) at the rate per unit volume of J · E for current density J and electric field E . Such decaying turbulence is well known to evolve toward a state with strongly intermittent plasma current. Here we decompose the electric field into components that are irrotational, E ir, and solenoidal (divergence-free), E so. E ir is associated with charge separation, and J · E ir is a rate of energy transfer between ions and electrons with little net change in plasma kinetic energy. Therefore, the net rate of conversion of electromagnetic energy to plasma kinetic energy is strongly dominated by J · E so, and for a strong guide magnetic field, this mainly involves the component E so,∥ parallel to the total magnetic field B . We examine various indicators of the spatial distribution of the energy transfer rate J ∥ · E so,∥, which relates to magnetic reconnection, the best of which are (1) the ratio of the out-of-plane electric field to the in-plane magnetic field, (2) the out-of-plane component of the nonideal electric field, and (3) the magnitude of the estimate of current helicity

scholarly journals Pitch angle scattering of an energetic magnetized particle by a circularly polarized electromagnetic wave

2021 ◽  
Author(s):  
Paul M. Bellan
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Wave ◽  
Kinetic Energy ◽  
Potential Energy ◽  
Pitch Angle ◽  
Energetic Electron ◽  
Circularly Polarized ◽  
Angle Scattering ◽  
Background Magnetic Field ◽  
Pseudo Potential

<p>The interaction between a circularly polarized electromagnetic wave and an energetic gyrating particle is described [1] using a relativistic pseudo-potential that is a function of the frequency mismatch,  a measure of the extent to which ω-k<sub>z</sub>v<sub>z</sub>=Ω/γ is not true. The description of this wave-particle interaction involves a sequence of relativistic transformations that ultimately demonstrate that the pseudo potential energy of a pseudo particle adds to a pseudo kinetic energy giving a total pseudo energy that is a constant of the motion. The pseudo kinetic energy is proportional to the square of the particle acceleration (compare to normal kinetic energy which is the square of a velocity) and the pseudo potential energy is a function of the mismatch and so effectively a function of the particle velocity parallel to the background magnetic field (compare to normal potential energy which is a function of position). Analysis of the pseudo-potential provides a means for interpreting particle motion in the wave in a manner analogous to the analysis of a normal particle bouncing in a conventional potential well.  The wave-particle  interaction is electromagnetic and so differs from and is more complicated than the well-known Landau damping of electrostatic waves.  The pseudo-potential profile depends on the initial mismatch, the normalized wave amplitude, and the initial angle between the wave magnetic field and the particle perpendicular velocity. For zero initial mismatch, the pseudo-potential consists of only one valley, but for finite mismatch, there can be two valleys separated by a hill. A large pitch angle scattering of the energetic electron can occur in the two-valley situation but fast scattering can also occur in a single valley. Examples relevant to magnetospheric whistler waves are discussed. Extension to the situation of a distribution of relativistic particles is presented in a companion talk [2].</p><p>[1] P. M. Bellan, Phys. Plasmas 20, Art. No. 042117 (2013)</p><p>[2] Y. D. Yoon and P. M. Bellan, JGR 125, Art. No. e2020JA027796 (2020)</p>

scholarly journals Magnetic Field Amplification and Polar Jet Formation in Protostars

1987 ◽  
Vol 115 ◽  
pp. 384-384
Author(s):  
S. Hinata
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
Kinetic Energy ◽  
Accretion Disk ◽  
Outer Edge ◽  
Moment Of Inertia ◽  
Simple Relationship ◽  
Field Amplification ◽  
Background Magnetic Field ◽  
The Moment

There is a simple relationship among moment of inertia I, rotational kinetic energy K, and momentum L given by (David Layzer, private communication), 2IK ≧ L. During the Hayashi phase a rotating protostar will amplify the trapped magnetic field by a dynamo-like process. Since the rotation is expected to be fast, many unstable modes will be excited and will grow exponentially in time until some nonlinear processes saturate the amplitude. However, it may happen that the reduction in rotational kinetic energy becomes so large that without increasing the moment of inertia the inequality given above may not be satisfied. The only way to increase the moment of inertia is to move the mass outward. This can be done by transferring the angular momentum outward through the magnetic field. So we will have a fast rotating mass shell at the outer edge of the star. Further transfer of angular momentum will push the shell against the accretion disk; the moving masses of the disk will divert the mass flow along the background magnetic field which extends perpendicular to the accretion disk. This results in the hollow cone jets from both poles because the outward motion is primarily on the equatorial plane.

Particle acceleration by interstellar plasma shock waves in non-uniform background magnetic field

2020 ◽  
Vol 498 (4) ◽  
pp. 5517-5523
Author(s):  
P Rashed-Mohassel ◽  
M Ghorbanalilu
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Shock Waves ◽  
Electric Field ◽  
Background Field ◽  
Magnetized Plasma ◽  
Background Magnetic Field ◽  
Positive Variation ◽  
Uniform Background ◽  
Plasma Shock

ABSTRACT Particle acceleration by plasma shock waves is investigated for a magnetized plasma cloud propagating in a non-uniform background magnetic field by means of analytical and numerical calculations. The mechanism studied here is mainly, magnetic trapping acceleration (MTA) which is previously investigated for a cloud moving through the uniform interstellar magnetic field (IMF). In this work, the acceleration is studied for a cloud moving in an antiparallel background field with spatial variations along the direction of motion. For negative variation, the cloud moves towards an antiparallel magnetic field with an increasing intensity, the trapped particle moves to locations with higher convective electric field and therefore gains more energy over time. For positive variation, the background field decreases to zero and changes into a parallel field with an increasing intensity. It is concluded that, when the background field vanishes, the MTA mechanism ceases and the particle escapes into the space. This leads to a bouncing acceleration which further increases energy of the gyrating particle. The two processes are followed by a shock drift acceleration, where due to the background magnetic field gradient, the particle drifts along the electric field and gains energy. Although for positive variation, three different mechanisms are involved, energy gain is less than in the case of a uniform background field.

Energy Conversion in the Electron Stagnation Region of Magnetopause Reconnection

2020 ◽  
Author(s):  
James Burch ◽  
James Webster ◽  
Kristina Pritchard ◽  
Kevin Genestreti ◽  
Michael Hesse ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Energy Conversion ◽  
Closed Field ◽  
Stagnation Region ◽  
Strong Electron ◽  
The Earth ◽  
Background Magnetic Field ◽  
Out Of Plane ◽  
Uniform Background ◽  
Field Lines

<p>For reconnection at the Earth’s day side, which is asymmetric, the main energy conversion occurs on closed field lines in the electron stagnation region. Energy conversion, as measured by <strong>J</strong>⦁<strong>E</strong>, occurs where out-of-plane electric field components are embedded within larger regions of out-of-plane current, which is carried by strong electron flows in the M direction of the LMN coordinate system. Bracketing these energy conversion sites are electron jet reversals (along L and -L) and converging  electron flows (along N and -N). These electron flows are like those that surround reconnection X lines, however, in these cases they occur completely within closed field lines. The question then is what, if anything, this energy conversion has to do with local reconnection of magnetic field lines. This paper reports on a study of two events observed by MMS on December 29, 2016 and April 15, 2018. The electron inflows have velocities between 0.05 V<sub>eA</sub> and 0.1 V<sub>eA</sub>, (V<sub>eA</sub> = electron Alfvén speed), which are consistent with predicted reconnection rates. Laboratory measurements and 3D simulation results offer some clues about how reconnecting current sheets can evolve in a uniform background magnetic field.</p>

Basic features of a charged particle dynamics in a laser beam with static axial magnetic field

2009 ◽  
Vol 17 (4) ◽  
Author(s):  
A. Dubik ◽  
M.J. Małachowski
Keyword(s):  
Magnetic Field ◽  
Charged Particle ◽  
Kinetic Energy ◽  
Electric Field ◽  
Laser Beam ◽  
Analytical Solutions ◽  
Axial Magnetic Field ◽  
Dynamic Equations ◽  
Graphical Form ◽  
Particle Rotation

AbstractIn this paper, the trajectory and kinetic energy of a charged particle, subjected to interaction from a laser beam containing an additionally applied external static axial magnetic field, have been analyzed. We give the rigorous analytical solutions of the dynamic equations. The obtained analytical solutions have been verified by performing calculations using the derived solutions and the well known Runge-Kutta procedure for solving original dynamic equations. Both methods gave the same results. The simulation results have been obtained and presented in graphical form using the derived solutions. Apart from the laser beam, we show the results for a maser beam. The obtained analytical solutions enabled us to perform a quantitative illustration, in a graphical form of the impact of many parameters on the shape, dimensions and the motion direction along a trajectory. The kinetic energy of electrons has also been studied and the energy oscillations in time with a period equal to the one of a particle rotation have been found. We show the appearance of, so-called, stationary trajectories (hypocycloid or epicycloid) which are the projections of the real trajectory onto the (x, y) plane. Increase in laser or maser beam intensity results in the increase in particle’s trajectory dimension which was found to be proportional to the amplitude of the electric field of the electromagnetic wave. However, external magnetic field increases the results in shrinking of the trajectories. Performed studies show that not only amplitude of the electric field but also the static axial magnetic field plays a crucial role in the acceleration process of a charged particle.At the authors of this paper best knowledge, the precise analytical solutions and theoretical analysis of the trajectories and energy gains by the charged particles accelerated in the laser beam and magnetic field are lacking in up to date publications. The authors have an intention to clarify partly some important aspects connected with this process. The presented theoretical studies apply for arbitrary charged particle and the attached figures-for electrons only.

Using Compressibility and Electric Field to Characterize Circularly-Polarized Waves Near the Proton Cyclotron Frequency Observed by Solar Orbiter

2021 ◽  
Author(s):  
Yuri Khotyaintsev ◽  
Daniel B Graham ◽  
Konrad Steinvall ◽  
Andris Vaivads ◽  
Milan Maksimovic ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Electric Field ◽  
Electromagnetic Waves ◽  
Cyclotron Frequency ◽  
Density Fluctuations ◽  
Background Magnetic Field ◽  
The Waves ◽  
The Magnetic Field ◽  
Proton Cyclotron

<p>We report Solar Orbiter observations of electromagnetic waves near the proton cyclotron frequency during the first perihelion. The waves have polarization close to circular and have wave vectors closely aligned with the background magnetic field. Such waves are potentially important for heating of the solar wind as their frequency and polarization allows effective energy exchange with solar wind protons. The Radio and Plasma Waves (RPW) instrument provides a high-cadence measurement of plasma density and electric field which we use together with the magnetic field measured by MAG to characterize these waves. In particular we compute the compressibility and the phase between the density fluctuations and the parallel component of the magnetic field, and show that these have a distinct behavior for the waves compared to the Alfvénic turbulence. We compare the observations to multi-fluid plasma dispersion and identify the waves modes corresponding to the observed waves. We discuss the importance of the waves for solar wind heating.</p>

MMS Observation of Intermittent Energy Dissipation in Magnetic Reconnection Diffusion Region

2021 ◽  
Author(s):  
Xiangcheng Dong ◽  
Malcolm Dunlop ◽  
Tieyan Wang ◽  
Jinsong Zhao ◽  
Huishan Fu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Energy Dissipation ◽  
Electric Field ◽  
Comparative Study ◽  
Spatial Effect ◽  
Diffusion Region ◽  
Common Phenomenon ◽  
Magnetospheric Multiscale ◽  
Out Of Plane ◽  
Current Behavior

<p>Magnetospheric Multiscale (MMS) data are used to investigate the energy dissipation in a  reconnection diffusion region at the magnetopause. The four MMS spacecraft were separated by about 10 km such that comparative study between each spacecraft within the diffusion region can be implemented. Similar magnetic field and electric current behavior between each spacecraft indicates the formation of a quasi-homogeneous diffusion region structure. However, we find that the energy dissipation results between each spacecraft are different due to the temporal or spatial effect of the out-of-plane merging electric field (E<sub>M</sub>) during the dissipation region. Our study suggests that the intermittent energy dissipation in the reconnection dissipation region can be a common phenomenon, even under a stable diffusion region structure.</p>

Transition to turbulent electric current sheet reconnection

1997 ◽  
Vol 57 (1) ◽  
pp. 35-45 ◽  
Author(s):  
RUSSELL B. DAHLBURG
Keyword(s):  
Magnetic Field ◽  
Energy Transfer ◽  
Kinetic Energy ◽  
Solar Corona ◽  
Electric Current ◽  
Magnetic Energy ◽  
Three Dimensional ◽  
Energy Losses ◽  
Neutral Sheet ◽  
Secondary Instabilities

Electric current sheets develop in the solar corona when different flux systems come into contact. At these sheets magnetic energy is transformed into heat and kinetic energy by means of reconnection. We have previously demonstrated how to accelerate neutral sheet energy conversion by means of a transition to turbulent reconnection via ideal, three-dimensional secondary instabilities, as conjectured by Montgomery. In this paper we describe how our previous results are modified by the presence of a finite mean sheetwise magnetic field. We find a stabilization from this field, due to a decrease in energy transfer from the basic magnetic field to the three-dimensional perturbed fields. An increase in perturbed dissipative energy losses is also observed.

Theoretical Model of Electric Field Tunable FMR Frequency of Magnetoelectric Tri-Layered Structure

2013 ◽  
Vol 303-306 ◽  
pp. 16-21
Author(s):  
Hao Miao Zhou ◽  
Qing Chen ◽  
Juan Hu Deng ◽  
Ying Xiao
Keyword(s):  
Magnetic Field ◽  
Theoretical Model ◽  
Electric Field ◽  
Frequency Shift ◽  
Free Energy Density ◽  
Coupling Mechanism ◽  
Mechanical Coupling ◽  
Out Of Plane ◽  
Magnetostriction Coefficient ◽  
Ferromagnetic Resonance Frequency

To study the magnetic-electrical-mechanical coupling mechanism of microwave ME (magnetoelectric) tri-layered structures, we proposed a theoretical model of electric tunable FMR (Ferromagnetic Resonance) frequency shift for bias magnetic field in different directions through the theory of Smith-Beljers and free energy density of ferrite. A deformation produced by the applied electric field called strain could be obtained through the theory of classical laminated plate. This model effectively predicts the stress of laminated structure increases when the piezoelectric coefficient increases, the shift of electric field tunable FMR frequency is more obvious when saturation magnetization and magnetostriction coefficient of ferrite increase. Moreover, it qualitatively explains the experimental phenomena that the directions of FMR frequency shift are opposite when apply the in-plane and out-of-plane magnetic field respectively, and provides a theoretical basis for electric field and magnetic field dual tunable microwave devices.

scholarly journals Особенности распространения стоячих электромагнитных и электронных волн в металлическом проводнике с электрическим переменным током проводимости

2021 ◽  
Vol 57 (6) ◽  
pp. 72-78
Author(s):  
М. И. Баранов ◽  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electromagnetic Waves ◽  
Average Velocity ◽  
Axial Flow ◽  
Electromagnetic Energy ◽  
Azimuthal Magnetic Field ◽  
Metallic Conductor ◽  
Velocity Of Propagation ◽  
Basic Features

The paper demonstrates the results of approximate calculations on the establishment of basic features of the propagation of standing transversal electromagnetic waves (EMWs) and standing longitudinal de Broglie electronic waves in a homogeneous not massive non-magnetic metallic conductor of finite dimensions (the radius r0 and the length l0 >>r0) with the alternating axial-flow current of conductivity of i0(t) of different peak-temporal parameters. The correlation for the rated estimation of the average velocity of propagation of the standing transversal EMWs and standing longitudinal de Broglie electronic waves in a metal (alloy) of the indicated conductor is presented. It is shown that quantized standing transversal EMWs arising in a metallic conductor of finite dimensions substantially differ from ordinary transversal EMWs, propagated in the conducting environments of unlimited dimensions. An important feature of the standing transversal EMWs in the examined conductor is the fact that their tension of an axial-flow electric-field advances by a phase their tension of an azimuthal magnetic-field on the corner of π/2. It was established that in the standing transversal EMWs of the used conductor the energy of their electric field only passes into the energy of their magnetic field and vice versa. Therefore the standing transversal EMWs do not transfer the flows of the electromagnetic energy on the surface of the studied conductor.

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