POP: Lasers, Particle Beams, Accelerators, Radiation Generation http://scitation.aip.org/ POP: Lasers, Particle Beams, Accelerators, Radiation Generation Optical field-ionization of a neutral gas with inhomogeneous density for electron acceleration by a high-intensity laser http://link.aip.org/link/?PHP/19/023103/1&agg=rss Devki Nandan Gupta, Kunwar Pal Singh, and Hyyong Suk<br/> A scheme for the laser-induced acceleration of an electron from a double-ionizing neutral gas is investigated, where an inhomogeneous neutral gas profile (resembling a gas-jet experiment) is considered in order to observe the actual electron energy gain during acceleration. Optical-field ionization ... [Phys. Plasmas 19, 023103 (2012)] published Fri Feb 3, 2012. Suppression of higher mode excitation in a high gain relativistic klystron amplifier http://link.aip.org/link/?PHP/19/023102/1&agg=rss Y. Wu, Z. Xu, X. Jin, Z. H. Li, and C. X. Tang<br/> Suppressing higher mode excitation is very important in the high gain relativistic klystron amplifier because higher mode can seriously degrade klystron performance and cause pulse shortening. The mechanism of higher mode self-excitation is explored in the PIC simulation, and it is shown the couplin ... [Phys. Plasmas 19, 023102 (2012)] published Fri Feb 3, 2012. A watt-class 1-THz backward-wave oscillator based on sine waveguide http://link.aip.org/link/?PHP/19/013113/1&agg=rss Xiong Xu, Yanyu Wei, Fei Shen, Hairong Yin, Jin Xu et al.<br/> A novel backward wave oscillator was proposed by utilizing a concise sine waveguide slow-wave structure combined with sheet electron beam to operate at terahertz frequency band. First, the design method was described, and the dispersion curve and interaction impedance of the sine waveguide were calc ... [Phys. Plasmas 19, 013113 (2012)] published Thu Jan 26, 2012. Novel electromagnetic radiation in a semi-infinite space filled with a double-negative metamaterial http://link.aip.org/link/?PHP/19/013112/1&agg=rss Zhaoyun Duan, Chen Guo, Jun Zhou, Jucheng Lu, and Min Chen<br/> We have theoretically investigated the electromagnetic radiation excited by a charged particle moving along a semi-infinite space filled with a double-negative metamaterial (DNM). Cherenkov radiation in the double-negative region exhibits reversed or backward radiation behavior. The spectral density ... [Phys. Plasmas 19, 013112 (2012)] published Thu Jan 26, 2012. Surpassing one x-ray photon per electron in nonlinear Thomson scattering in 180 degrees geometry http://link.aip.org/link/?PHP/19/013111/1&agg=rss Shihua Zhao, Qingzheng Lv, Suying Yuan, and Yingjun Li<br/> We have obtained the general analytical expressions of harmonic radiation for Thomson scattering (TS) of arbitrary polarized laser by virtue of generalized Bessel functions and derived the extremum conditions for backscattered harmonics. Especially, for the fundamental backscattered Thomson scatteri ... [Phys. Plasmas 19, 013111 (2012)] published Thu Jan 26, 2012. Comparisons between nonlinear kinetic modelings of simulated Raman scattering using envelope equations http://link.aip.org/link/?PHP/19/013110/1&agg=rss Didier Benisti, Nikolai A. Yampolsky, and Nathaniel J. Fisch<br/> In this paper, we compare two recent models [N. A. Yampolsky and N. J. Fisch, Phys. Plasmas 16, 072104 (2009); D. Benisti, D. J. Strozzi, L. Gremillet, and O. Morice, Phys. Rev. Lett. 103, 155002 (2009)] introduced to predict the nonlinear growth of stimulated Raman scattering in the kinetic regime, ... [Phys. Plasmas 19, 013110 (2012)] published Tue Jan 24, 2012. The dispersion relation and excitation of transverse magnetic mode electromagnetic waves in rippled-wall waveguide with a plasma rod and an annular dielectric http://link.aip.org/link/?PHP/19/013109/1&agg=rss M. Nejati and B. Shokri<br/> By using the linear field theory, the dispersion relation of electromagnetic waves in a rippled-wall waveguide with a plasma rod and an annular dielectric is obtained. In addition, by injecting a finite thick annular intense relativistic electron beam in this waveguide, the excitation of these waves ... [Phys. Plasmas 19, 013109 (2012)] published Mon Jan 23, 2012. Bremsstrahlung of fast electrons in long air gaps http://link.aip.org/link/?PHP/19/013108/1&agg=rss E. V. Oreshkin, S. A. Barengolts, S. A. Chaikovsky, A. V. Oginov, K. V. Shpakov et al.<br/> The results of an experiment on discharges in long atmospheric pressure air gaps at a pulsed voltage of amplitude up to 800 kV and risetime 150200 ns have been analyzed. In the experiment, a radiation pulse of photon energy >5 keV and duration 1020 ns was observed. In analyzing the experimental data ... [Phys. Plasmas 19, 013108 (2012)] published Fri Jan 20, 2012. Efficiency enhancement in free-electron laser amplifier with one dimensional helical wiggler and ion-channel guiding http://link.aip.org/link/?PHP/19/013107/1&agg=rss F. Jafari Bahman and B. Maraghechi<br/> A method for efficiency enhancement in free-electron laser is studied which uses both tapered wiggler magnetic field and ion-channel density. Derivation of a set of nonlinear and coupled differential equations leads to the self-consistent description of the evolution of both an ensemble of electrons ... [Phys. Plasmas 19, 013107 (2012)] published Fri Jan 20, 2012. Measuring of plasma properties indu[cyrillic es]ed by non-vacuum electron beam welding http://link.aip.org/link/?PHP/19/013106/1&agg=rss U. Reisgen, M. Schleser, A. Abdurakhmanov, and A. Gumenyuk<br/> Electron beam plasma measurement was realised by means of DIABEAM system invented by ISF RWTH Aachen. The Langmuir probe method is used for measurement. The relative simplicity of the method and the possibility of dispersion of high power on the probe allow its application for the investigation of h ... [Phys. Plasmas 19, 013106 (2012)] published Wed Jan 18, 2012. Experimental demonstration of a compact high efficient relativistic magnetron with directly axial radiation http://link.aip.org/link/?PHP/19/013105/1&agg=rss Wei Li, Yong-gui Liu, Ting Shu, Han-wu Yang, Yu-wei Fan et al.<br/> A compact relativistic magnetron with axial microwave radiation is experimentally investigated. Under the modified magnetic field distribution, only connecting a special horn antenna in the axial direction, the relativistic magnetron can stably radiate high power and high efficiency microwaves. The ... [Phys. Plasmas 19, 013105 (2012)] published Tue Jan 17, 2012. Femtosecond laser-plasma interaction with prepulse-generated liquid metal microjets http://link.aip.org/link/?PHP/19/013104/1&agg=rss D. S. Uryupina, K. A. Ivanov, A. V. Brantov, A. B. Savel'ev, V. Yu. Bychenkov et al.<br/> Ultrashort laser pulse interaction with a microstructured surface of a melted metal is a promising source of hard x-ray radiation. Microstructuring is achieved by a weak prepulse that produces narrow high-density microjets. As an x-ray source, the interaction of the main laser pulse with such jets i ... [Phys. Plasmas 19, 013104 (2012)] published Tue Jan 17, 2012. Micro focusing of fast electrons with opened cone targets http://link.aip.org/link/?PHP/19/013103/1&agg=rss Feng Liu<!--orlang--> (&#x5218;&#x5CF0;)<!--orlang-->, Xiaoxuan Liu<!--orlang--> (&#x6797;&#x6653;&#x5BA3;)<!--orlang-->, Bicheng Liu<!--orlang--> (&#x5218;&#x5FC5;&#x6210;)<!--orlang-->, Wenjun Ding<!--orlang--> (&#x4E01;&#x6587;&#x541B;)<!--orlang-->, Fei Du<!--orlang--> (&#x675C;&#x98DE;)<!--orlang--> et al.<br/> Using opened reentrant cone silicon targets, we have demonstrated the effect of micro focusing of fast electrons generated in intense laser-plasma interactions. When an intense femtosecond laser pulse is focused tightly onto one of the side walls of the cone, fast electron beam emitted along the sid ... [Phys. Plasmas 19, 013103 (2012)] published Fri Jan 6, 2012. Radiation pressure acceleration of corrugated thin foils by Gaussian and super-Gaussian beams http://link.aip.org/link/?PHP/19/013102/1&agg=rss K. Adusumilli, D. Goyal, and V. K. Tripathi<br/> Rayleigh-Taylor instability of radiation pressure accelerated ultrathin foils by laser having Gaussian and super-Gaussian intensity distribution is investigated using a single fluid code. The foil is allowed to have ring shaped surface ripples. The radiation pressure force on such a foil is non-unif ... [Phys. Plasmas 19, 013102 (2012)] published Thu Jan 5, 2012. Resonant third-harmonic generation of a short-pulse laser from electron-hole plasmas http://link.aip.org/link/?PHP/19/013101/1&agg=rss Niti Kant, Devki Nandan Gupta, and Hyyong Suk<br/> In semiconductors, free carriers are created in pairs in inter-band transitions and consist of an electron and its corresponding hole. At very high carrier densities, carrier-carrier collisions dominate over carrier-lattice collisions and carriers begin to behave collectively to form plasma. Here, w ... [Phys. Plasmas 19, 013101 (2012)] published Thu Jan 5, 2012. Terahertz generation from laser filaments in the presence of a static electric field in a plasma http://link.aip.org/link/?PHP/18/123106/1&agg=rss Lalita Bhasin and V. K. Tripathi<br/> Two femtosecond laser pulses with frequencies omega and omega that undergo filamentation in a plasma couple nonlinearly in the presence of a transverse, static electric field to generate terahertz wave at the frequency omega-omega. The coupling is enhanced in the presence of the static electric fiel ... [Phys. Plasmas 18, 123106 (2011)] published Thu Dec 29, 2011. Energetics and energy scaling of quasi-monoenergetic protons in laser radiation pressure acceleration http://link.aip.org/link/?PHP/18/123105/1&agg=rss Tung-Chang Liu, Xi Shao, Chuan-Sheng Liu, Jao-Jang Su, Bengt Eliasson et al.<br/> Theoretical and computational studies of the ion energy scaling of the radiation pressure acceleration of an ultra-thin foil by short pulse intense laser irradiation are presented. To obtain a quasi-monoenergetic ion beam with an energy spread of less than 20%, two-dimensional particle-in-cell simul ... [Phys. Plasmas 18, 123105 (2011)] published Thu Dec 29, 2011. Plasma-based multistage virtual cathode radiation http://link.aip.org/link/?PHP/18/123104/1&agg=rss Dong Su and Changjian Tang<br/> A plasma-based multistage virtual cathode radiation is proposed. Multistage virtual cathode can be formed as an electron beam passes through a high dense ion background. The reflected electrons can be coupled with transverse magnetic wave, and electromagnetic radiation is detected. Unlike the tradit ... [Phys. Plasmas 18, 123104 (2011)] published Tue Dec 27, 2011. Modeling of 10 GeV-1 TeV laser-plasma accelerators using Lorentz boosted simulations http://link.aip.org/link/?PHP/18/123103/1&agg=rss J.-L. Vay, C. G. R. Geddes, E. Esarey, C. B. Schroeder, W. P. Leemans et al.<br/> Modeling of laser-plasma wakefield accelerators in an optimal frame of reference [J.-L. Vay, Phys. Rev. Lett. 98, 130405 (2007)] allows direct and efficient full-scale modeling of deeply depleted and beam loaded laser-plasma stages of 10 GeV-1 TeV (parameters not computationally accessible otherwise ... [Phys. Plasmas 18, 123103 (2011)] published Tue Dec 13, 2011. Collective microdynamics and noise suppression in dispersive electron beam transport http://link.aip.org/link/?PHP/18/123102/1&agg=rss Avraham Gover, Egor Dyunin, Tamir Duchovni, and Ariel Nause<br/> A general formulation is presented for deep collective interaction micro-dynamics in dispersive e-beam transport. In the regime of transversely coherent interaction, the formulation is applicable to both coherent and random temporal modulation of the electron beam. We demonstrate its use for determi ... [Phys. Plasmas 18, 123102 (2011)] published Fri Dec 9, 2011. Equation of motion with radiation reaction in ultrarelativistic laser-electron interactions http://link.aip.org/link/?PHP/18/123101/1&agg=rss Keita Seto, Hideo Nagatomo, James Koga, and Kunioki Mima<br/> The intensity of the ultra-short pulse lasers has reached 10 W/cm owing to the advancements of laser technology. When the motion of an electron becomes relativistic, bremsstrahlung accompanies it. The energy from this bremsstrahlung corresponds to the energy loss of the electron; therefore, the moti ... [Phys. Plasmas 18, 123101 (2011)] published Fri Dec 2, 2011.