Nonlinear triggering process of whistler-mode rising-tone emissions in a homogeneous magnetic field

Abstract We perform an electromagnetic particle simulation of triggered emissions in a uniform magnetic field for understanding of nonlinear wave-particle interaction in the vicinity of the magnetic equator. A finite length of a whistler-mode triggering wave packet with a constant frequency is injected by oscillating an external current at the equator. We find that the first subpacket of rising-tone triggered emissions is generated after termination of the injection of the triggering wave in the homogeneous magnetic field. By analyzing resonant currents and resonant electron dynamics in the simulation, we find that the formation of an electron hole in a velocity phase space forms resonant currents, and the currents cause wave amplification and frequency increase. As the very initial stage of the generation process, phase-bunching occurs at the wavefront of the triggering wave. The phase-bunching is caused by the rotation of electrons in the velocity phase space because of the gradient of the distribution function in the parallel velocity. The phase-bunched untrapped electrons are scattered to the loss cone giving energy to the electromagnetic waves, while the electrons in the low density region are trapped by the wave potential, forming an electron hole. The time scale of the initial formation process of the electron hole is related to the duration time of the triggering wave necessary for generation of triggered emissions. The duration time is determined by the interaction time. For the generation of triggered emissions, the interaction time is more than 1/4 of the nonlinear trapping period in the present simulation.

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Simulation study on nonlinear frequency shift of narrow band whistler-mode waves in a homogeneous magnetic field

Earth Planets and Space ◽

10.1186/bf03352013 ◽

2006 ◽

Vol 58 (9) ◽

pp. 1219-1225 ◽

Cited By ~ 6

Author(s):

Yuto Katoh ◽

Yoshiharu Omura

Keyword(s):

Magnetic Field ◽

Frequency Shift ◽

Simulation Study ◽

Narrow Band ◽

Homogeneous Magnetic Field ◽

Nonlinear Frequency ◽

Whistler Mode ◽

Whistler Mode Waves ◽

Nonlinear Frequency Shift

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Early-Time Non-Equilibrium Pitch Angle Diffusion of Electrons by Whistler-Mode Hiss in a Plasmaspheric Plume Associated with BARREL Precipitation

Frontiers in Astronomy and Space Sciences ◽

10.3389/fspas.2021.776992 ◽

2021 ◽

Vol 8 ◽

Author(s):

R. M. Millan ◽

J.-F. Ripoll ◽

O. Santolík ◽

W. S. Kurth

Keyword(s):

Phase Space ◽

Pitch Angle ◽

Particle Interaction ◽

Phase Space Density ◽

Angle Distribution ◽

Loss Cone ◽

Linear Diffusion ◽

Whistler Mode ◽

Space Density ◽

Van Allen Probes

In August 2015, the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) observed precipitation of energetic (<200 keV) electrons magnetically conjugate to a region of dense cold plasma as measured by the twin Van Allen Probes spacecraft. The two spacecraft passed through the high density region during multiple orbits, showing that the structure was spatial and relatively stable over many hours. The region, identified as a plasmaspheric plume, was filled with intense hiss-like plasma waves. We use a quasi-linear diffusion model to investigate plume whistler-mode hiss waves as the cause of precipitation observed by BARREL. The model input parameters are based on the observed wave, plasma and energetic particle properties obtained from Van Allen Probes. Diffusion coefficients are found to be largest in the same energy range as the precipitation observed by BARREL, indicating that the plume hiss waves were responsible for the precipitation. The event-driven pitch angle diffusion simulation is also used to investigate the evolution of the electron phase space density (PSD) for different energies and assumed initial pitch angle distributions. The results show a complex temporal evolution of the phase space density, with periods of both growth and loss. The earliest dynamics, within the ∼5 first minutes, can be controlled by a growth of the PSD near the loss cone (by a factor up to ∼2, depending on the conditions, pitch angle, and energy), favored by the absence of a gradient at the loss cone and by the gradients of the initial pitch angle distribution. Global loss by 1-3 orders of magnitude (depending on the energy) occurs within the first ∼100 min of wave-particle interaction. The prevalence of plasmaspheric plumes and detached plasma regions suggests whistler-mode hiss waves could be an important driver of electron loss even at high L-value (L ∼6), outside of the main plasmasphere.

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Magnetic field turbulence, electron heating, magnetic holes, proton cyclotron waves, and the onsets of bipolar pulse (electron hole) events: a possible unifying scenario

Nonlinear Processes in Geophysics ◽

10.5194/npg-10-27-2003 ◽

2003 ◽

Vol 10 (1/2) ◽

pp. 27-35 ◽

Cited By ~ 19

Author(s):

B. T. Tsurutani ◽

B. Dasgupta ◽

J. K. Arballo ◽

G. S. Lakhina ◽

J. S. Pickett

Keyword(s):

Magnetic Field ◽

Pulse Electron ◽

Bipolar Pulse ◽

Ion Heating ◽

Electron Hole ◽

Loss Cone ◽

Electron Heating ◽

Field Lines ◽

Electron Holes ◽

Proton Cyclotron

Abstract. Two electron heating events have been identified on 20 May 1996 when Polar was in the polar cap/polar cusp boundary layer. The electron heating events were located within magnetic holes/cavities/bubbles and were accompanied by nonlinear ± 14 nT peak-to-peak (f ~ 0.6 to 0.7 fcp) obliquely propagating proton cyclotron waves. The electrons appear to be heated isotropically. Electric bipolar pulse (electron hole) onset events were also detected within the heating events. We propose a scenario which can link the above phenomena. Nonlinear Alfvén waves, generated through cusp magnetic reconnection, propagate down magnetic field lines and locally heat electrons through the ponderomotive force. The magnetic cavity is created through the diamagnetic effect of the heated electrons. Ion heating also occurs through ponderomotive acceleration (but much less than the electrons) and the protons generate the electromagnetic proton cyclotron waves through the loss cone instability. The obliquely propagating electromagnetic proton cyclotron waves accelerate bi-streaming electrons, which are the source of free energy for the electron holes.

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Analysis of magneto rheological elastomers for energy harvesting systems

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209350 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 439-446

Author(s):

Gildas Diguet ◽

Gael Sebald ◽

Masami Nakano ◽

Mickaël Lallart ◽

Jean-Yves Cavaillé

Keyword(s):

Magnetic Field ◽

Energy Harvesting ◽

Shear Strain ◽

Magnetic Induction ◽

Magnetic Particles ◽

Homogeneous Magnetic Field ◽

Electrical Signal ◽

Harvesting Systems ◽

Dc Bias ◽

Magneto Rheological

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.

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HALL CONDUCTIVITY AS THE TOPOLOGICAL INVARIANT IN PHASE SPACE IN THE PRESENCE OF INTERACTIONS AND NON-UNIFORM MAGNETIC FIELD

Письма в Журнал экспериментальной и теоретической физики ◽

10.1134/s0370274x19190081 ◽

2019 ◽

Vol 110 (7-8 (10)) ◽

pp. 480-481 ◽

Cited By ~ 3

Author(s):

C.X. ZHANG ◽

M.A. ZUBKOV

Keyword(s):

Magnetic Field ◽

Phase Space ◽

Uniform Magnetic Field ◽

Topological Invariant ◽

Hall Conductivity

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Notizen: Effect of Magnetic Field on Ascorbic Acid Oxidase Activity, I

Zeitschrift für Naturforschung C ◽

10.1515/znc-1986-0319 ◽

1986 ◽

Vol 41 (3) ◽

pp. 355-358 ◽

Cited By ~ 4

Author(s):

V. S. Ghole ◽

P. S. Damle ◽

W. H.-P. Thiemann

Keyword(s):

Magnetic Field ◽

Ascorbic Acid ◽

Homogeneous Magnetic Field ◽

Acid Oxidase ◽

High Substrate Concentration ◽

Ascorbic Acid Oxidase ◽

Rate Of Reaction ◽

Substrate Concentrations ◽

Burk Plot

A homogeneous magnetic field of 1.1 T strength exhibits a significant influence on the activity of the enzyme ascorbic acid oxidase in vitro. A Lineweaver-Burk plot of the reaction shows the typical pattern of a mixed-type inhibition, i.e. a larger rate of reaction at low substrate concentrations and a smaller rate of reaction at high substrate concentration than that of the control without magnetic field applied.

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Double layers in the downward current region of the aurora

Nonlinear Processes in Geophysics ◽

10.5194/npg-10-45-2003 ◽

2003 ◽

Vol 10 (1/2) ◽

pp. 45-52 ◽

Cited By ~ 32

Author(s):

R. E. Ergun ◽

L. Andersson ◽

C. W. Carlson ◽

D. L. Newman ◽

M. V. Goldman

Keyword(s):

Magnetic Field ◽

Electron Beam ◽

Phase Space ◽

Electric Field ◽

Electric Fields ◽

Double Layers ◽

Parallel Electric Field ◽

Electrostatic Waves ◽

Current Region ◽

Decisive Evidence

Abstract. Direct observations of magnetic-field-aligned (parallel) electric fields in the downward current region of the aurora provide decisive evidence of naturally occurring double layers. We report measurements of parallel electric fields, electron fluxes and ion fluxes related to double layers that are responsible for particle acceleration. The observations suggest that parallel electric fields organize into a structure of three distinct, narrowly-confined regions along the magnetic field (B). In the "ramp" region, the measured parallel electric field forms a nearly-monotonic potential ramp that is localized to ~ 10 Debye lengths along B. The ramp is moving parallel to B at the ion acoustic speed (vs) and in the same direction as the accelerated electrons. On the high-potential side of the ramp, in the "beam" region, an unstable electron beam is seen for roughly another 10 Debye lengths along B. The electron beam is rapidly stabilized by intense electrostatic waves and nonlinear structures interpreted as electron phase-space holes. The "wave" region is physically separated from the ramp by the beam region. Numerical simulations reproduce a similar ramp structure, beam region, electrostatic turbulence region and plasma characteristics as seen in the observations. These results suggest that large double layers can account for the parallel electric field in the downward current region and that intense electrostatic turbulence rapidly stabilizes the accelerated electron distributions. These results also demonstrate that parallel electric fields are directly associated with the generation of large-amplitude electron phase-space holes and plasma waves.

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Finite Element Analysis of Magnetic Field Exciter for Direct Testing of Magnetocaloric Materials’ Properties

Energies ◽

10.3390/en14102792 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2792

Author(s):

Wieslaw Lyskawinski ◽

Wojciech Szelag ◽

Cezary Jedryczka ◽

Tomasz Tolinski

Keyword(s):

Magnetic Field ◽

Finite Element ◽

Magnetic Circuit ◽

Homogeneous Magnetic Field ◽

Element Analysis ◽

Mcm Testing ◽

Testing Region ◽

Magnetocaloric Materials ◽

Field Excitation ◽

The Magnetic Field

The paper presents research on magnetic field exciters dedicated to testing magnetocaloric materials (MCMs) as well as used in the design process of magnetic refrigeration systems. An important element of the proposed test stand is the system of magnetic field excitation. It should provide a homogeneous magnetic field with a controllable value of its intensity in the MCM testing region. Several concepts of a magnetic circuit when designing the field exciters have been proposed and evaluated. In the MCM testing region of the proposed exciters, the magnetic field is controlled by changing the structure of the magnetic circuit. A precise 3D field model of electromagnetic phenomena has been developed in the professional finite element method (FEM) package and used to design and analyze the exciters. The obtained results of the calculations of the magnetic field distribution in the working area were compared with the results of the measurements carried out on the exciter prototype. The conclusions resulting from the conducted research are presented and discussed.

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