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Resonant Enhancement of THz Radiation Through Vertically Aligned Carbon Nanotubes Array by Applying Wiggler Magnetic Field
摘要： The present analysis develops a novel theory of terahertz radiation generation by beating of two laser beams, incident obliquely on the array of vertically aligned carbon nanotubes (CNTs) in the presence of an external wiggler magnetic field. The array of CNTs behaves as nanoantenna to generate THz radiations. The incident lasers exert a ponderomotive force on the electrons of the CNTs to produce nonlinear oscillatory velocity, which beats with the applied wiggler magnetic field. This beating produces a nonlinear current at (ω2 ? ω1, k2 ? k1 + k0) which acts as an antenna to produce the THz radiation. We observe that when the beat frequency (ω2 ? ω1) lies near the effective plasmon frequency of the CNTs, strong THz radiation is produced due to a resonant interaction of the laser with CNT electrons. The externally applied wiggler magnetic field enhances the efficiency of THz radiation of nanoantenna by providing the necessary momentum to the generated THz radiation. We explore the impact of radius and length of nanotubes on the efficiency of THz generation. The generated THz power is enhanced at an optimum angle of incidence of lasers with an array of CNTs.
关键词： THz radiation,Carbon nanotubes,Antenna theory,Wiggler magnetic field,Plasma,Nanotechnology
更新于2025-09-23 15:23:52
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Second-harmonic generation by a chirped laser pulse with the exponential density ramp profile in the presence of a planar magnetostatic wiggler
摘要： Second-harmonic generation of the relativistic self-focused chirped laser pulse in plasma has been studied with the exponential plasma density ramp profile in the presence of a planar magnetostatic wiggler. It is evident that the exponential plasma density ramp is helpful in enhancing second-harmonic generation as, with the introduction of the exponential plasma density ramp, self-focusing becomes stronger and hence, it leads to enhance the harmonic generation of the second order in the plasma. Also, it is observed that the efficiency of second-harmonic generation enhances significantly with an increase in the value of the chirp parameter. Further, the magnetostatic wiggler helps in enhancing the harmonic generation of the second order. This is due to the fact that dynamics of the oscillating electrons is altered due to the Lorentz force which, in turn, modifies the plasma wave and, hence, results in the efficient second-harmonic generation.
关键词： Chirped laser pulse,magnetostatic wiggler,second-harmonic generation,exponential density ramp profile
更新于2025-09-12 10:27:22
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Excitation modes in a cylindrical plasma waveguide with helical wiggler field and ion channel guiding
摘要： Analysis of high frequency eigen modes of a cylindrical metallic waveguide filled with a helical wiggler and a relativistic electron beam and guiding by an ion-channel is presented. A relativistic nonlinear wave equation is derived in a form including the coupling of EH, HE, HE betatron (HE - Be), and EH betatron (EH - Be) modes due to ion channel guiding and wiggler magnetic field. Six families of eigen modes are found. The cutoff frequencies in TM, TE modes are illustrated for this configuration.
关键词： Ion-channel guiding,waveguide,Eigen modes,Helical wiggler field
更新于2025-09-11 14:15:04
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - The SPS and an alternative ring design as pre-booster of FCC e+e? injector
摘要： The FCC-e+e? injector complex needs to produce and to transport a high-intensity e+/e? beam at a fast repetition rate for topping up the collider at its collision energy. Two di?erent options are under consideration as pre-accelerator before the bunches are transferred to the high-energy booster: using the existing SPS and a completely new ring. The purpose of this paper is to present the necessary modi?cations of the existing SPS which is mainly adding damping and Robinson wigglers to reach the required emittance for SPS and the updates on conceptual design of an alternative accelerator ring with injection and extraction energies of 6 and 20 GeV, respectively. In this study, the main parameters of both choices are established, including the optics design and layout updates.
关键词： SPS,Robinson wiggler,FCC-e+e? injector,pre-booster ring,alternative ring design,damping wiggler
更新于2025-09-04 15:30:14
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Electromagnetic Wave Theory for Calculation of Exact Magnetic Field in Case of BWO
摘要： Overall efficiency of high power microwave generating device depends upon input current in the form of electron beam and currents required for electromagnets. In order to increase the efficiency of device, if electromagnets are replaced by permanent magnets, overall efficiency of device shall increase. So, calculation of exact magnetic field is required. In this paper, the exact relation of magnetic field required in high power microwave generation using Backward Wave Oscillator (BWO) is found. BWO interacts with slow waves and is the most promising device to produce high power microwaves. The interaction involves the beams from high current density and the waveguide mode. An exact relation that specifically relates the various parameters of the waveguide like slow wave structures (SWS) dimensions, input beam voltage and operational frequency with axial magnetic field is derived. The derived equation gives calculation of exact values of magnetic field for focusing of beams. Theoretical and simulated work show good agreement with the previously available experimental data. So, with the derived electromagnetic wave relation exact value of magnetic field is calculated for desired frequency and power regime.
关键词： High current electron,High power microwave,Wiggler,Magnetic field,Oscillator
更新于2025-09-04 15:30:14