scholarly journals Lower hybrid oscillations in multicomponent space plasmas subjected to ion cyclotron waves

1997 ◽  
Vol 102 (A1) ◽  
pp. 175-184 ◽  
Author(s):  
G. V. Khazanov ◽  
E. N. Krivorutsky ◽  
T. E. Moore ◽  
M. W. Liemohn ◽  
J. L. Horwitz
Keyword(s):  
Space Plasmas ◽  
Lower Hybrid ◽  
Ion Cyclotron Waves ◽  
Ion Cyclotron

scholarly journals Ultrahigh resolution simulations of mode converted ion cyclotron waves and lower hybrid waves

2004 ◽  
Vol 164 (1-3) ◽  
pp. 330-335 ◽  
Author(s):  
J.C. Wright ◽  
P.T. Bonoli ◽  
E. D'Azevedo ◽  
M. Brambilla
Keyword(s):  
Lower Hybrid ◽  
Ultrahigh Resolution ◽  
Ion Cyclotron Waves ◽  
Ion Cyclotron ◽  
Hybrid Waves ◽  
Lower Hybrid Waves

Direct Measurement of Ion Cyclotron Resonance Between Wave Fields and Protons in Space Plasmas

2021 ◽  
Author(s):  
Qiaowen Luo ◽  
Xingyu Zhu ◽  
Jiansen He ◽  
Jun Cui ◽  
Hairong Lai ◽  
...  
Keyword(s):  
Kinetic Theory ◽  
Electric Field ◽  
Velocity Distribution ◽  
Wave Field ◽  
Cyclotron Resonance ◽  
Space Plasmas ◽  
Ion Cyclotron Resonance ◽  
Wave Fields ◽  
Ion Cyclotron Waves ◽  
Ion Cyclotron

<p>Ion cyclotron resonance is one of the fundamental energy conversion processes through wave field-particle interaction in collisionless plasma. However, the key evidence for cyclotron resonance (i.e., the coherence between wave field and ion phase space density pertaining to the ion cyclotron resonance and responsible for the dissipation of ion cyclotron waves (ICWs)) has yet to be directly observed. Based on the high-quality measurements of space plasma by the Magnetospheric Multiscale (MMS) satellites, we observe that both the wave electromagnetic field vectors and the disturbed ion velocity distribution rotate around the background magnetic field. Moreover, we find that the gyrophase angle difference between the fluctuations in the ion velocity distribution functions and the wave electric field vectors are always in the range of (0, 90) degrees, clearly suggesting the ongoing energy conversion from wave fields to particles. By invoking plasma kinetic theory, we find that the field-particle correlation for the dissipative ion cyclotron waves in the theoretical model matches well with our observations. Furthermore, all the wave electric field vectors (Ewave), the ion current (Ji) and the energy transfer rate (Ji ·Ewave) exhibit quasi-periodic oscillations, and the frequency of Ji ·Ewave is about twice the frequency of Ewave and Ji, consistent with plasma kinetic theory. Therefore, our combined analysis of MMS observations and kinetic theory provides direct, thorough, and comprehensive evidence for ICW dissipation in space plasmas.</p>

Origin of the zebra structure in the Jovian decameter radio emission

2020 ◽  
Vol 645 ◽  
pp. A31
Author(s):  
V. E. Shaposhnikov ◽  
G. V. Litvinenko ◽  
V. V. Zaitsev ◽  
V. V. Zakharenko ◽  
A. A. Konovalenko
Keyword(s):  
Lower Hybrid ◽  
Height Distribution ◽  
Plasma Parameters ◽  
Extended Source ◽  
Ion Cyclotron Waves ◽  
Proposed Model ◽  
Ion Cyclotron ◽  
Magnetic Field Model ◽  
Decameter Radio ◽  
Upper Ionosphere

Context. We discuss the origin of quasi-harmonic emission bands that have been observed in the dynamic spectra of the Jovian decameter emission. Aims. We aim to show that the interpretation of the observed structure can be based on the effect of double plasma resonance (DPR) at ion cyclotron harmonics. Methods. According to the proposed model, in the extended source in the upper ionosphere of Jupiter, where the DPR condition is satisfied for one of the ion cyclotron frequency harmonics, the ion cyclotron waves are effectively excited at the frequency of the lower hybrid resonance. The observed electromagnetic radiation with a quasi-harmonic structure arises due to scattering of ion cyclotron waves by supra-thermal electrons. Results. Based on the VIP4 magnetic field model, we determine the longitudes at which the source of the considered radiation can be located. The obtained estimates of the plasma density and its height distribution in the source, as well as the energies of emitting ions and scattering electrons provide information about the plasma parameters in the upper ionosphere of Jupiter. Furthermore, these estimates are in good agreement with the observational data.

scholarly journals Interaction of radio frequency waves with cylindrical density filaments: scattering and radiation pressure

2021 ◽  
Vol 87 (6) ◽  
Author(s):  
Spyridon I. Valvis ◽  
Abhay K. Ram ◽  
Kyriakos Hizanidis
Keyword(s):  
Radio Frequency ◽  
Cold Plasma ◽  
Radiation Force ◽  
Edge Plasma ◽  
Lower Hybrid ◽  
Maxwell Stress Tensor ◽  
Ion Cyclotron Waves ◽  
Ion Cyclotron ◽  
Rf Antenna ◽  
The Waves

The propagation of radio-frequency (RF) waves in tokamaks can be affected by filamentary structures, or blobs, that are present in the edge plasma and the scrape-off layer. The difference in the permittivity between the surrounding plasma and interior of a filament leads to reflection, refraction and diffraction of the waves. This, in turn, can affect the power flow into the core of the plasma and reduce the efficiency of heating and/or current generation. The scattering of RF waves, lower hybrid, helicon and ion cyclotron waves, by a single cylindrical filament, embedded in a background plasma, is studied using a full-wave analytical theory developed previously (Ram & Hizanidis, Phys. Plasmas, vol. 23, 2016, 022504). The theory assumes that the plasma in and around a filament is homogeneous and cold. A detailed scattering analysis reveals a variety of common features that exist among the three distinctly different RF waves. These common attributes can be inferred intuitively based on an examination of the cold plasma dispersion relation. The physical intuition is a useful step to understanding experimental observations on scattering, as well as results from simulations that include general forms of edge plasma turbulence. While a filament can affect the propagation of RF waves, the radiation force exerted by the waves can influence the filament. The force on a filament is determined using the Maxwell stress tensor. In 1905, Poynting was the first to evaluate and measure the radiation force on an interface separating two different dielectric media (Poynting, London Edinburgh Dublin Philos. Mag. J. Sci., vol. 9, 1905, pp. 393–406). For ordinary light propagating in vacuum and incident on a glass surface, Poynting noted that the surface is ‘pulled’ towards the vacuum. In a magnetized cold plasma, there are two independent wave modes. Even if only one of these modes is excited by an RF antenna, a filament will couple power to the other mode: a consequence of electromagnetic boundary conditions. This facet of scattering has consequences on the radiation force that go beyond Poynting's seminal contribution. The direction of the force depends on the polarization of the incident wave and on the mode structure of the waves inside and in the vicinity of a filament. It can either pull the filament toward the RF source or push it away. For slow lower hybrid waves, filaments with densities greater than the ambient density are pulled in, while filaments with lower densities are pushed out, thereby enhancing the density in front of the antenna. In the case of fast helicon and ion cyclotron waves, the direction of the force depends on the plasma and wave parameters; in particular, on the ambient density. The radiation force, in all three frequency ranges, is large enough to affect the motion of a filament and could be measured experimentally. This also suggests the possibility of modifying the edge turbulence using RF waves.

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