Whistler modes excited by magnetic antennas: A review

Stenzel, R. L.

doi:10.1063/1.5097852

Cited by 17 publications

(11 citation statements)

References 123 publications

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“…two TG modes with identical radial structure but opposite azimuthal mode numbers. For this we draw on the inductive antenna design reviewed by Stenzel (2019).…”

Section: Faraday–fresnel Rotation For Tg Wavesmentioning

confidence: 99%

“…Because of the low-frequency nature of these waves, the displacement current in the Maxwell–Ampère equation can be neglected, and propagation is characterised by the dispersion relation given in (2.3). Both antennae designs to excite this WH branch (Stenzel & Urrutia 2014; Urrutia & Stenzel 2015 b ; Stenzel 2019) and the angular momentum dynamics of these waves (Stenzel & Urrutia 2015 a ; Stenzel & Urrutia 2015 b ; Urrutia & Stenzel 2015 a ; Urrutia & Stenzel 2016; Stenzel & Urrutia 2018) have been extensively investigated.…”

Section: Faraday–fresnel Rotation For Wh Wavesmentioning

confidence: 99%

“…To conclude this section we point here to a coupling structure designed to launch WH modes of the type (5.19). This type of antenna has been extensively investigated, both theoretically and experimentally, in Stenzel & Urrutia (2014) and Urrutia & Stenzel (2015 b ), and we refer the readers to the review paper by Stenzel (2019) for an in-depth analysis of their properties.…”

Section: Faraday–fresnel Rotation For Wh Wavesmentioning

confidence: 99%

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Faraday–Fresnel rotation and splitting of orbital angular momentum carrying waves in a rotating plasma

Rax

Gueroult

2021

J. Plasma Phys.

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Rotational Fresnel drag – or orbital Faraday rotation – in a rotating magnetised plasma is uncovered and studied analytically for Trivelpiece–Gould and whistler–helicon waves carrying orbital angular momentum (OAM). Plasma rotation is shown to introduce a non-zero phase shift between OAM-carrying eigenmodes with opposite helicities, similarly to the phase shift between spin angular momentum eigenmodes associated with the classical Faraday effect in a magnetised plasma at rest. By examining the dispersion relation for these two low-frequency modes in a Brillouin rotating plasma, this Faraday–Fresnel rotation effect is traced back to the combined effects of Doppler shift, centrifugal forces and Coriolis forces. In addition, the longitudinal group velocity in the presence of rotation is shown to depend both on rotation and azimuthal mode, therefore predicting the Faraday–Fresnel splitting of the envelope of a wave packet containing a superposition of OAM-carrying eigenmodes with opposite helicities.

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“…two TG modes with identical radial structure but opposite azimuthal mode numbers. For this we draw on the inductive antenna design reviewed by Stenzel (2019).…”

Section: Faraday–fresnel Rotation For Tg Wavesmentioning

confidence: 99%

Section: Faraday–fresnel Rotation For Wh Wavesmentioning

confidence: 99%

Section: Faraday–fresnel Rotation For Wh Wavesmentioning

confidence: 99%

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Faraday–Fresnel rotation and splitting of orbital angular momentum carrying waves in a rotating plasma

Rax

Gueroult

2021

J. Plasma Phys.

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“…Our results demonstrate the possibility to transmit high power in space and validated the design and technology for further high-power space-borne VLF transmitters. The physical understanding obtained in this study will also provide a guide to laboratory whistler mode wave injection experiments 24 , especially in controlled fusion 25 .…”

Section: Introductionmentioning

confidence: 79%

High-Power VLF Transmission Experiment in the Radiation Belts: Initial Result from the DSX Mission

Song

Galkin

et al. 2022

Preprint

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Space weather phenomena threaten the space assets that bring us services via space technologies, such as the Global Positioning System, communication systems with satellite relays, and most global TV broadcast networks, which have provided unprecedented convenience to everyday life and opportunities to businesses. A hazard among phenomena1 is the population of relativistic electrons in the region called Van Allan radiation belts2. These electrons can be trapped for years once produced by either natural3 or artificial processes4 and can damage the electronics and degrade the solar panels on satellites. Intense investigations have begun with recently launched NASA satellites, Van Allen Belt Probes A and B in 20125-13. To remedy the threat and reduce the resulting damage, artificial processes can be introduced to shorten the lifetime of these particles14 with mechanisms such as pitch-angle diffusion through wave-particle interaction15-17 by transmitting very-low-frequency (VLF) waves into radiation belts. To directly transmit the VLF waves in space is an extremely challenging task, and previous theoretical and numerical predictions of the radiation impedance differ more than five orders in magnitude18-23. Here we show the measurements of radiation impedance from high-power VLF wave transmission experiments in the radiation belts to help settle the dispute of the previous studies. The measured radiation reactance disagrees with the most influential theoretical model18,19,22 and the vacuum model, but proves the plasma sheath model and simulation of the antenna-plasma interaction20,21,23. A new discovery is that the measured radiation resistance decreases as the transmission frequency increases. Our results demonstrate the possibility to transmit high power in space and validated the design and technology for further high-power space-borne VLF transmitters. The physical understanding obtained in this study will also provide a guide to laboratory whistler mode wave injection experiments24, especially in controlled fusion25.

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“…The former arise from time-varying magnetic fields, the latter are caused by space charge imbalances between mobile electrons and slow ions. The pulsed electrode acts like an antenna and the current collected is a wave current [34,35,36].…”

Section: Relaxation Instabilities Of Positive Electrodes In Magmentioning

confidence: 99%

Untitled

2021

J. Technol. Space Plasmas

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The properties of sheaths and associated potential structures and instabilities cover a broad field which even a review cannot cover everything. Thus, the focus will be on about a dozen examples, describe their observations and focus on the basic physical explanations for the effects, while further details are found in the references. Due to familiarity the review focuses mainly on the authors work but compared and referenced related work. The topics start with a high frequency oscillation near the electron plasma frequency. Low frequency instabilities also occur at the ion plasma frequency. The injection of ions into an electron-rich sheath widens the sheath and forms a double layer. Likewise, the injection of electrons into an ion rich sheath widens and establishes a double layer which occurs in free plasma injection into vacuum. The sheath widens and forms a double layer by ionization in an electron rich sheath. When particle fluxes in "fireballs" gets out of balance the double layer performs relaxation instabilities which has been studied extensively. Fireballs inside spherical electrodes create a new instability due to the transit time of trapped electrons. On cylindrical and spherical electrodes the electron rich sheath rotates in magnetized plasmas. Electrons rotate due to E × B 0 which excites electron drift waves with azimuthal eigenmodes. Conversely a permanent magnetic dipole has been used as a negative electrode. The impact of energetic ions produces secondary electron emission, forming a ring of plasma around the magnetic equator. Such "magnetrons" are subject to various instabilities. Finally, the current to a positively biased electrode in a uniformly magnetized plasma is unstable to relaxation oscillations, which shows an example of global effects. The sheath at the electrode raises the potential in the flux tube of the electrode thereby creating a radial sheath which moves unmagnetized ions radially. The ion motion creates a density perturbation which affects the electrode current. If the electrode draws large currents the current disruptions create large inductive voltages on the electrode, which again produce double layers. This phenomenon has been seen in reconnection currents. Many examples of sheath properties will be explained. Although the focus is on the physics some examples of applications will be suggested such as neutral gas heating and accelerating, sputtering of plasma magnetrons and rf oscillators.

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Whistler modes excited by magnetic antennas: A review

Cited by 17 publications

References 123 publications

Faraday–Fresnel rotation and splitting of orbital angular momentum carrying waves in a rotating plasma

Faraday–Fresnel rotation and splitting of orbital angular momentum carrying waves in a rotating plasma

High-Power VLF Transmission Experiment in the Radiation Belts: Initial Result from the DSX Mission

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