Difference frequency harmonic ion heating using Whistler modes

1970 ◽  
Vol 48 (11) ◽  
pp. 1386-1409 ◽  
Author(s):  
C. E. Capjack ◽  
C. R. James
Keyword(s):  
Magnetic Field ◽  
Electric Fields ◽  
Kinetic Equations ◽  
Magnetized Plasma ◽  
Natural Mode ◽  
Heating Process ◽  
Ion Heating ◽  
Mixed Wave ◽  
Nonlinear Mixing ◽  
Frequency Harmonic

The heating of ions in a magnetized plasma by the second-order electric fields generated through the nonlinear mixing of two Whistler modes is examined. The kinetic equations describing the mixing and heating process are solved using the method of orbit integrations. Two techniques are available for optimizing the energy absorbed by the ions. One is to allow the mixed wave to approach a natural mode in the plasma, resulting in a field resonance. A second method is to have the ions absorb energy through cyclotron damping. The latter technique and the combination of the two optimizing schemes will be investigated. The resulting sensitivities to fluctuations in frequency, density, static magnetic field, and the direction of propagation of the source waves will be given.

DIFFERENCE FREQUENCY HARMONIC ION HEATING

1967 ◽  
Vol 45 (5) ◽  
pp. 1771-1781 ◽  
Author(s):  
C. R. James ◽  
W. B. Thompson
Keyword(s):  
High Frequency ◽  
Collision Frequency ◽  
Difference Frequency ◽  
Fourth Power ◽  
Heating Process ◽  
Ion Heating ◽  
Frequency Signal ◽  
Transverse Waves ◽  
The Difference ◽  
Frequency Harmonic

The heating of a magnetized hot diffuse plasma using the difference frequency signal generated from two high-frequency (35 GHz) transverse waves is examined. The plasma is described by the cold plasma model and a series expansion of harmonics is used to obtain a solution to the equations. It is shown that the energy absorbed by the ions can be made inversely proportional to the collision frequency and the fourth power of the driven frequency and proportional to the fourth power of the driven electric field intensity. An investigation of the sensitivity of the heating process to fluctuations in frequency, density, and d-c. magnetic field is carried out.

scholarly journals A quasilinear operator retaining magnetic drift effects in tokamak geometry

2017 ◽  
Vol 83 (6) ◽  
Author(s):  
Peter J. Catto ◽  
Jungpyo Lee ◽  
Abhay K. Ram
Keyword(s):  
Magnetic Field ◽  
Diffusion Equation ◽  
Radio Frequency ◽  
Uniform Magnetic Field ◽  
Resonance Condition ◽  
Kinetic Equations ◽  
Current Drive ◽  
Magnetized Plasma ◽  
Angle Variation ◽  
Quasilinear Operator

The interaction of radio frequency waves with charged particles in a magnetized plasma is usually described by the quasilinear operator that was originally formulated by Kennel & Engelmann (Phys. Fluids, vol. 9, 1966, pp. 2377–2388). In their formulation the plasma is assumed to be homogenous and embedded in a uniform magnetic field. In tokamak plasmas the Kennel–Engelmann operator does not capture the magnetic drifts of the particles that are inherent to the non-uniform magnetic field. To overcome this deficiency a combined drift and gyrokinetic derivation is employed to derive the quasilinear operator for radio frequency heating and current drive in a tokamak with magnetic drifts retained. The derivation requires retaining the magnetic moment to higher order in both the unperturbed and perturbed kinetic equations. The formal prescription for determining the perturbed distribution function then follows a novel procedure in which two non-resonant terms must be evaluated explicitly. The systematic analysis leads to a diffusion equation that is compact and completely expressed in terms of the drift kinetic variables. The equation is not transit averaged, and satisfies the entropy principle, while retaining the full poloidal angle variation without resorting to Fourier decomposition. As the diffusion equation is in physical variables, it can be implemented in any computational code. In the Kennel–Engelmann formalism, the wave–particle resonant delta function is either for the Landau resonance or the Doppler shifted cyclotron resonance. In the combined gyro and drift kinetic approach, a term related to the magnetic drift modifies the resonance condition.

scholarly journals Simulation study of wake field excitation in interaction of intense laser and magnetized plasma: Half-sine pulse shape (HSPS) and trapezoid pulse shape (TPS)

2017 ◽  
Vol 57 (2) ◽  
Author(s):  
Amir Rahimian ◽  
Hossien Zahed
Keyword(s):  
Magnetic Field ◽  
Electric Fields ◽  
Pulse Shape ◽  
Laser Wavelength ◽  
Magnetized Plasma ◽  
Intense Laser ◽  
Plasma Parameters ◽  
Particle In Cell ◽  
Wake Field ◽  
Field Excitation

We have conducted particle-in-cell (PIC) simulations of a linearly polarized intensive laser pulse with two different envelopes propagating through a homogeneous fully ionized cold plasma. It is shown that the amplitude of the wake field depends on laser wavelength, pulse duration, electron number density and envelope shape. We have also simulated the effect of applying a longitudinal magnetic field on the wake field excitation process. It is observed that magnetic field enhances the wake field and increases its intensity in all cases. Our results are in agreement with the analytical results presented by Askari and Shahidani [Opt. Laser Technol.45, 613–619 (2013)] and can help choosing the optimum values of affecting laser and plasma parameters in order to reach high accelerating wake electric fields.

An improved hierarchy for turbulent magnetized plasma Part 1. Theory

1972 ◽  
Vol 7 (2) ◽  
pp. 337-362
Author(s):  
Eldon J. Linnebur ◽  
Terry Kammash
Keyword(s):  
Magnetic Field ◽  
Correlation Function ◽  
Time Dependence ◽  
Projection Operator ◽  
Kinetic Equations ◽  
Time Correlation ◽  
Time Correlation Function ◽  
Turbulent Plasma ◽  
Magnetized Plasma ◽  
Consistent Manner

The kinetic equations for infinite homogeneous turbulent plasma in a magnetic field are analyzed using a projection operator which allows the time dependence to be maintained in a more exact and consistent manner than has been possible heretofore. By introducing approximations on the multi-time correlation function rather than the fluctuations, as is conventionally done, a hierarchy of equations is obtained which predicts different behaviour for the system especially in connexion with wave-wave interations. These effects are further highlighted by showing how the present results reduce to those obtained by various authors.

scholarly journals Double layers in the downward current region of the aurora

2003 ◽  
Vol 10 (1/2) ◽  
pp. 45-52 ◽  
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.

Effects of a Vertical Magnetic Field on Particle Confinement in a Magnetized Plasma Torus

2004 ◽  
Vol 93 (16) ◽  
Author(s):  
S. H. Müller ◽  
A. Fasoli ◽  
B. Labit ◽  
M. McGrath ◽  
M. Podestà ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetized Plasma ◽  
Vertical Magnetic Field ◽  
Plasma Torus ◽  
Particle Confinement

TRANSPARENCY OF NARROW CONSTRICTIONS IN A GRAPHENE SINGLE ELECTRON TRANSISTOR

2009 ◽  
Vol 23 (12n13) ◽  
pp. 2647-2654 ◽  
Author(s):  
C. STAMPFER ◽  
E. SCHURTENBERGER ◽  
F. MOLITOR ◽  
J. GÜTTINGER ◽  
T. IHN ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Fields ◽  
Drain Current ◽  
Single Electron ◽  
Single Electron Transistor ◽  
Perpendicular Magnetic Field ◽  
Current Saturation ◽  
Tunnel Barriers ◽  
Graphene Island ◽  
Charging Energy

We report on electronic transport experiments on a graphene single electron transistor as function of a perpendicular magnetic field. The device, which consists of a graphene island connected to source and drain electrodes via two narrow graphene constrictions is electronically characterized and the device exhibits a characteristic charging energy of approx. 3.5 meV. We investigate the homogeneity of the two graphene "tunnel" barriers connecting the single electron transistor to source and drain contacts as function of laterally applied electric fields, which are also used to electrostatically tune the overall device. Further, we focus on the barrier transparency as function of an applied perpendicular magnetic field and we find an increase of transparency for increasing magnetic field and a source-drain current saturation for magnetic fields exceeding 5 T.

scholarly journals Simulation of mode conversion process from upper-hybrid waves to LO-mode waves in the vicinity of the plasmapause

2010 ◽  
Vol 28 (6) ◽  
pp. 1289-1297 ◽  
Author(s):  
M. J. Kalaee ◽  
Y. Katoh ◽  
A. Kumamoto ◽  
T. Ono ◽  
Y. Nishimura
Keyword(s):  
Density Gradient ◽  
Electric Fields ◽  
Numerical Experiments ◽  
Mode Conversion ◽  
Equatorial Region ◽  
Magnetized Plasma ◽  
Conversion Process ◽  
Observation Data ◽  
Linear Mode ◽  
Wave Normal

Abstract. In order to clarify the role of the mode conversion process in the generation mechanism of LO-mode waves in the equatorial region of the plasmasphere, we have investigated the linear mode conversion process among upper-hybrid-resonance (UHR)-mode, Z-mode and LO-mode waves by a numerical simulation solving Maxwell's equations and the equation of motion of a cold electron fluid. The wave coupling process occurring in the cold magnetized plasma are examined in detail. In order to give a realistic initial plasma condition in the numerical experiments, we use initial parameters inferred from observation data obtained around the generation region of LO-mode waves obtained by the Akebono satellite. A density gradient is estimated from the observed UHR frequency, and wave normal angles are estimated from the dispersion relation of cold plasma by comparing observed wave electric fields. Then, we perform numerical experiments of mode conversion processes using the density gradient of background plasma and the wave normal angle of incident upper hybrid mode waves determined from the observation results. We found that the characteristics of reproduced LO-mode waves in each simulation run are consistent with observations.

Orientation Control in Multilayered Alumina Prepared Using Electrophoretic Deposition in a Strong Magnetic Field

2007 ◽  
Vol 29-30 ◽  
pp. 223-226
Author(s):  
Tohru Suzuki ◽  
Tetsuo Uchikoshi ◽  
Koji Morita ◽  
Keijiro Hiraga ◽  
Yoshio Sakka
Keyword(s):  
Magnetic Field ◽  
Strong Magnetic Field ◽  
Electric Fields ◽  
Electrophoretic Deposition ◽  
Layer By Layer ◽  
Colloidal Processing ◽  
Orientation Control ◽  
Laminar Composites ◽  
Oriented Layer

We have reported that development of texture can be controlled by colloidal processing in a strong magnetic field followed by heating even for diamagnetic ceramics such as alumina, titania and so on. We demonstrate in this study that alumina/alumina laminar composites with different crystalline-oriented layer are produced by electrophoretic deposition (EPD) in a strong magnetic field. This composite was fabricated by alternately changing the angle between the directions of the magnetic and electric fields layer by layer during EPD in 12T. The grains in alternate layers are aligned differently.

A Case for Magneto Hydro Dynamics (MHD)

2001 ◽  
Author(s):  
Haim H. Bau
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Lorentz Force ◽  
Electric Fields ◽  
Biological Fluids ◽  
Fluid Volume ◽  
Chaotic Advection ◽  
Complex Flows ◽  
Electric Currents

Abstract In this paper, I review some of our work on the use of magneto hydrodynamics (MHD) for pumping, controlling, and stirring fluids in microdevices. In many applications, one operates with liquids that are at least slightly conductive such as biological fluids. By patterning electrodes inside flow conduits and subjecting these electrodes to potential differences, one can induce electric currents in the liquid. In the presence of a magnetic field, a Lorentz force is generated in a direction that is perpendicular to both the magnetic and electric fields. Since one has a great amount of freedom in patterning the electrodes, one can induce forces in various directions so as to generate complex flows including “guided” flows in virtual, wall-less channels. The magnetic flux generators can be either embedded in the device or be external. Despite their unfavorable scaling (the magnitude of the forces is proportional to the fluid volume), MHD offers many advantages such as the flexibility of applying forces in any desired direction and the ability to adjust the magnitude of the forces by adjusting either the electric and/or magnetic fields. We provide examples of (i) MHD pumps; (ii) controlled networks of conduits in which each conduit is equipped with a MHD actuator and by controlling the voltage applied to each actuator, one can direct the liquid to flow in any desired way without a need for valves; and (iii) MHD stirrers including stirrers that exhibit chaotic advection.

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