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Published in Dikshitulu K. Kalluri, Principles of Electromagnetic Waves and Materials, 2017
Dikshitulu K. Kalluri, R.K. Shrivastava
The electromagnetic wave interaction with relativistic plasmas has been receiving considerable attention in recent literature. A number of investigators [1–14] have studied the problem of reflection and transmission of electromagnetic waves by semi-infinite moving dielectric media and plasmas as well as dielectric slabs. Yeh [15,16] studied the reflection and transmission of electromagnetic waves by a moving isotropic plasma slab, whereas Chawla and Unz [17] considered the case of normal incidence on a moving plasma slab subjected to a finite static magnetic field normal to the slab. Kong and Cheng [18] obtained numerical results for the transmission coefficient at normal incidence when the uniaxial plasma slab is moving along the interface and the technique used was based on the concept of bianisotropy.
Plasma-Based Particle Acceleration Technology
Published in Hitendra K. Malik, Laser-Matter Interaction for Radiation and Energy, 2021
The production of immense amplitude and relativistic plasma waves are of great interest because of their potential to accelerate the particles with ultrahigh gradients. The plasma waves can be excited by ultrashort intense laser pulses or beating of two frequency lasers, so that these waves propagate with the phase velocity close to speed of light. To achieve this, mainly two mechanisms, LWFA and PBWA, are used. The latter one is explained in this section. As mentioned above, plasma wave propagating with a velocity close to the speed of light results in the generation of the concept of charge separation, which in turn produces a longitudinal electrostatic field. Such longitudinal electrostatic fields are responsible for the acceleration in PBWAs. The plasma wave would be produced if the frequency difference of two collinear laser pulses is in such a way that the plasma frequency matches with the beat frequency. Initially Tajima and Dawson (1979) proposed the concept of PBWA, in which two long pulse (10-9 sec) laser beams were spatially overlapped in the plasma, with their frequency difference equivalent to the plasma frequency, i.e. Δω˜ωp. This allowed them to produce intensity high enough to resonantly excite plasma oscillations, while simultaneously fulfilling the restriction on the pulse width. The concept of PBWA was further investigated by many groups, but the best experimental results in that time were reported by Clayton et al. (1993, 1994) at University of California, Los Angeles (UCLA), where a sequence of PBWA experiments adopting two lines of CO2 laser in the plasma of density ∼1015 cm−3 were conducted (Clayton et al. 1993, 1994; Marsh 1994; Esarey et al. 1996). Clayton et al. (1993) was the first group to demonstrate the ultrahigh acceleration gradient of externally inserted electrons in relativistic wakefields excited by the beating of two laser beams. The experimental setup used by this team is shown in Figure 6.4.
Dispersion of electromagnetic waves in coaxial cylindrical rippled-wall waveguide including plasma layer
Published in Waves in Random and Complex Media, 2022
F. Asadiamiri, K. Chaudhary, J. Ali, M. Bahadoran, Malihe Nejati, P. P. Yupapin, A. R. Niknam
Like terahertz radiation, the high-power microwave radiation has the potential for various applications such as microwave communications, radars, therapy and diagnostics of disorders of thermoregulation, and perhaps best known by most people, cooking [5,14–16]. Moreover, it is well known that the presence of plasma can increase the efficiency of microwave sources. For example, plasma sources can be used as highly efficient microwave oscillators based on relativistic electron beam-plasma interaction [17]. Significant efforts have been done to develop plasma sources and investigate the characteristics of the plasma in relativistic plasma microwave electronics. As plasma comprises of charged particles (electrons and ions) and subject to several natural oscillations in the different frequency ranges.
Slow and fast modulation instability and envelope solitons of ion-acoustic wave in electron–ion–positron plasma having ion stream and superthermal electrons
Published in Radiation Effects and Defects in Solids, 2021
S. N. Paul, A. Roychowdhury, Indrani Paul, S. Chaudhuri
Our present analysis can be applied to study the modulation instability in relativistic plasma which would be useful to understand many non-linear phenomena occurring in space and laboratory plasma. In fact, relativistic effect significantly modify the linear and non-linear behaviour of plasma waves. The relativistic plasma occurs in variety of situations, such as space-plasmas (50), laser–plasma interaction (51) and plasma sheet boundary layer of earth’s magnetosphere (52). The relativistic motion in plasmas is assumed to exist during the early evolution of the Universe (53). In astrophysical observations, it has been found that particles are ejected with high velocities during solar bursts or the explosion of stars huge amounts of matter in the form of ionised gases are ejected from these astrophysical objects at very high velocities (54–59). Recently, Paul et al. (60 ) have studied modulation instability in a fully relativistic plasma having non-thermal electrons. It is seen that slow and fast modulation instability, envelope solitons may be excited in fully relativistic plasma in the presence of the non-thermal electrons.
Chiral fermion asymmetry in high-energy plasma simulations
Published in Geophysical & Astrophysical Fluid Dynamics, 2020
J. Schober, A. Brandenburg, I. Rogachevskii
The Pencil Code1 is designed for exploring the dynamical evolution of turbulent, compressible, and magnetised plasmas in the MHD limit. It is, in particular, suitable for studying a large variety of cosmic plasmas and astrophysical systems from planets and stars, to the interstellar medium, galaxies, the intergalactic medium, and cosmology. In its basic configuration, the Pencil Code solves the equations of classical MHD, which describe the evolution of the mass density, ρ, the magnetic field strength, , the velocity, , and the temperature, T. Interestingly, this set of dynamical variables has to be extended in the limit of high energies, where a new degree of freedom, the chiral chemical potential, arises from the chiral magnetic effect (CME). This anomalous fermionic quantum effect emerges within the standard model of high energy particle physics and describes the generation of an electric current along the magnetic field if there is an asymmetry between the number density of left- and right-handed fermions. The CME modifies the Maxwell equations and leads to a system of chiral MHD equations, which turn into classical MHD when the chiral chemical potential vanishes. In this paper, we describe how the CME affects a relativistic plasma and how it can be explored with a new module in the Pencil Code.