Whistler waves with angular momentum in space and laboratory plasmas and their counterparts in free space

Stenzel, R. L.

doi:10.1080/23746149.2016.1240017

Cited by 37 publications

(17 citation statements)

References 146 publications

(170 reference statements)

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“…Plasma acceleration and heating by electromagnetic waves is of great importance in many research topics such as parametric instabilities [1], collisionless shocks and turbulence [2], planetary magnetospheres [3,4], and inertial and magnetic confinement fusion (ICF and MCF) [5][6][7]. Among different types of waves, the whistler wave, which is a low-frequency electromagnetic wave traveling along an external magnetic field B ext , often plays a major role in the generation of energetic particles [3,4]. Whistler-mode chorus waves are one of the most intense plasma waves observed in planetary magnetospheres [8][9][10][11][12] and expected as a promising mechanism to produce relativistic electrons [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Ultrafast wave-particle energy transfer in the collapse of standing whistler waves

et al. 2019

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Efficient energy transfer from electromagnetic waves to ions has been demanded to control laboratory plasmas for various applications and could be useful to understand the nature of space and astrophysical plasmas. However, there exists a severe unsolved problem that most of the wave energy is converted quickly to electrons, but not to ions. Here, an energy conversion process to ions in overdense plasmas associated with whistler waves is investigated by numerical simulations and theoretical model. Whistler waves propagating along a magnetic field in space and laboratories often form the standing waves by the collision of counter-propagating waves or through the reflection. We find that ions in the standing whistler waves acquire a large amount of energy directly from the waves in a short timescale comparable to the wave oscillation period. Thermalized ion temperature increases in proportion to the square of the wave amplitude and becomes much higher than the electron temperature in a wide range of wave-plasma conditions. This efficient ion-heating mechanism applies to various plasma phenomena in space physics and fusion energy sciences.

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Section: Introductionmentioning

confidence: 99%

Ultrafast wave-particle energy transfer in the collapse of standing whistler waves

et al. 2019

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“…Landau and Doppler-shifted cyclotron resonance exist not only for the linear field momentum but also for the angular orbital momentum. 9 The transverse Doppler shift has so far received little attention.…”

Section: Introductionmentioning

confidence: 99%

Whistler modes in highly nonuniform magnetic fields. III. Propagation near mirror and cusp fields

Stenzel

Urrutia

2018

Physics of Plasmas

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The properties of helicon modes in highly nonuniform magnetic fields are studied experimentally. The waves propagate in an essentially unbounded uniform laboratory plasma. Helicons with mode number m ¼ 1 are excited with a magnetic loop with dipole moment across the dc magnetic field. The wave fields are measured with a three-component magnetic probe movable in three orthogonal directions so as to resolve the spatial and temporal wave properties. The ambient magnetic field has the topology of a mirror or a cusp, produced by the superposition of a uniform axial field B 0 and the field of a current-carrying loop with the axis along B 0. The novel finding is the reflection of whistlers by a strong mirror magnetic field. The reflection arises when the magnetic field changes on a scale length shorter than the whistler wavelength. The simplest explanation for the reflection mechanism is the strong gradient of the refractive index which depends on the density and magnetic field. More detailed observations show that the incident wave splits when the k vector makes an angle larger than 90 with respect to B 0 which produces a parallel phase velocity component opposite to that of the incident wave. The reflection coefficient has been estimated to be close to unity. Interference between reflected and incident waves creates nodes in which the whistler mode becomes linearly polarized. When the magnetic field topology is that of a reversed field configuration (FRC), the incident wave is absorbed near the three-dimensional (3D) magnetic null point which prevents wave reflections. However, waves outside the separatrix are not absorbed and continue to propagate around the null point. When waves are excited inside the FRC, their polarization and helicon mode are reversed. Implications of these observations on research in space plasmas and helicon sources are pointed out.

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“…It can be verified that in the case where the half-space y < 0 is filled with a resonant magnetoplasma, for which sgn ε = sgn η, Equations (25) and (26) are reduced to the results of [31] if the plasma is sufficiently dense such that |εη| ε 2 a . In contrast to [31], the representations in Equations (25) and (26) turn out to be valid for arbitrary plasma parameters, regardless of the signs and values of ε and η.…”

Section: Solution Of Integral Equations For the Antenna Currentmentioning

confidence: 99%

“…This problem, which turns out to be very difficult even for the simplest antennas operated in magnetized plasmas, has been solved only for some canonical antenna geometries [9][10][11][12][13][14][15][16]. Recently, increased attention has been paid to the features of excitation and propagation of electromagnetic waves in the presence of cylindrical magnetized plasma structures [23][24][25][26], and new results for loop antennas located on the surface of such structures have been obtained using the integral equation method [27,28]. In particular, the current distribution and input impedance of a circular loop antenna located on the surface of an axially magnetized plasma column in a homogeneous dielectric medium have been found.…”

Section: Introductionmentioning

confidence: 99%

Theory of a Strip Antenna Located at the Interface of an Isotropic Medium and a Magnetoplasma

Kudrin¹,

Zaitseva²,

Zaboronkova³

et al. 2018

PIER C

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A study is made of the electrodynamic characteristics of an antenna having the form of a perfectly conducting, infinitesimally thin, narrow strip located at a plane interface of an isotropic medium and a cold collisionless magnetoplasma. The antenna is perpendicular to an external static magnetic field superimposed on the plasma medium and is excited by a time-harmonic given voltage. Singular integral equations for the antenna current are obtained in the case of an infinitely long strip conductor. Based on the solution of these equations, the current distribution and input impedance of the antenna are found for nonresonant and resonant frequency ranges of the magnetoplasma. The limits of applicability of an approximate approach employing the transmission line theory for determining the antenna characteristics are established. Within the framework of this approach, the results obtained are generalized to the case of a finite-length strip antenna.

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Whistler waves with angular momentum in space and laboratory plasmas and their counterparts in free space

Cited by 37 publications

References 146 publications

Ultrafast wave-particle energy transfer in the collapse of standing whistler waves

Ultrafast wave-particle energy transfer in the collapse of standing whistler waves

Whistler modes in highly nonuniform magnetic fields. III. Propagation near mirror and cusp fields

Theory of a Strip Antenna Located at the Interface of an Isotropic Medium and a Magnetoplasma

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