Collimated Fast Electron Emission from Long Wires Irradiated by Intense Femtosecond Laser Pulses

Tokita, Shigeki; Otani, K.; Nishoji, Toshihiko; Inoue, Shunsuke; Hashida, Masaki; Shimizu, Shuji

doi:10.1103/physrevlett.106.255001

Cited by 29 publications

(25 citation statements)

References 19 publications

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“…Whatever energy is not dissipated at low wavenumber finds its way to high perpendicular wavenumber where it undergoes a cascade. 38 The associated spectrum has been measured in a set of carefully constructed high resolution runs.…”

Section: Gyrokinetic Simulation Of Itg Spectrummentioning

confidence: 99%

Dissipation range turbulent cascades in plasmas

et al. 2012

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Dissipation range cascades in plasma turbulence are described and spectra are formulated from the scaled attenuation in wavenumber space of the spectral energy transfer rate. This yields spectra characterized by the product of a power law and exponential fall-off, applicable to all scales. Spectral indices of the power law and exponential fall-off depend on the scaling of the dissipation, the strength of the nonlinearity, and nonlocal effects when dissipation rates of multiple fluctuation fields are different. The theory is used to derive spectra for MHD turbulence with magnetic Prandtl number greater than unity, extending previous work. The theory is also applied to generic plasma turbulence by considering the spectrum from damping with arbitrary wavenumber scaling. The latter is relevant to ion temperature gradient turbulence modeled by gyrokinetics. The spectrum in this case has an exponential component that becomes weaker at small scale, giving a power law asymptotically. Results from the theory are compared to three very different types of turbulence. These include the magnetic plasma turbulence of the Madison Symmetric Torus, the MHD turbulence of liquid metal in the Madison Dynamo Experiment, and gyrokinetic simulation of ion temperature gradient turbulence.

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Section: Gyrokinetic Simulation Of Itg Spectrummentioning

confidence: 99%

Dissipation range turbulent cascades in plasmas

et al. 2012

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“…The processes of energy conversion and transport through the relativistic interactions of high-intensity laser pulses ( I > 10 18 W/cm 2 ) with solid targets have been widely investigated for their potential applications, such as ion acceleration 18 , fast ignition fusion 19 , and terahertz wave generation. Some remarkable phenomena have also been observed in relativistic laser interactions with wire targets 20 21 22 23 24 25 . Field propagation at the speed of light along a wire has been observed by laser-driven proton radiography 22 and is attributed to a transient current with a peak magnitude of the order of 10 4 A.…”

mentioning

confidence: 84%

Strong sub-terahertz surface waves generated on a metal wire by high-intensity laser pulses

Tokita

Shimizu

Nagashima

et al. 2015

Sci Rep

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Terahertz pulses trapped as surface waves on a wire waveguide can be flexibly transmitted and focused to sub-wavelength dimensions by using, for example, a tapered tip. This is particularly useful for applications that require high-field pulses. However, the generation of strong terahertz surface waves on a wire waveguide remains a challenge. Here, ultrafast field propagation along a metal wire driven by a femtosecond laser pulse with an intensity of 1018 W/cm2 is characterized by femtosecond electron deflectometry. From experimental and numerical results, we conclude that the field propagating at the speed of light is a half-cycle transverse-magnetic surface wave excited on the wire and a considerable portion of the kinetic energy of laser-produced fast electrons can be transferred to the sub-surface wave. The peak electric field strength of the surface wave and the pulse duration are estimated to be 200 MV/m and 7 ps, respectively.

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“…Assuming a Gaussian longitudinal profile, then the ratio of the energies measured after the filters can be used to characterize the radiation spectrum and so yields an estimate for the bunch length. This method is particularly suitable for the diagnostic of measuring the ultrashort bunch length in ultrafast electron diffraction applications with rf compression schemes [30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Generation and measurement of velocity bunched ultrashort bunch of pC charge

Tang

et al. 2015

Phys. Rev. ST Accel. Beams

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In this paper, we discuss the velocity compression in a short rf linac of an electron bunch from a rf photoinjector operated in the blowout regime. Particle tracking simulations shows that with a beam charge of 2 pC an ultrashort bunch duration of 16 fs can be obtained at a tight longitudinal focus downstream of the linac. A simplified coherent transition radiation (CTR) spectrum method is developed to enable the measurement of ultrashort (sub-50 fs) bunches at low bunch energy (5 MeV) and low bunch charges (<10 pC). In this method, the ratio of the radiation energy selected by two narrow bandwidth filters is used to estimate the bunch length. The contribution to the coherent form factor of the large transverse size of the bunch suppresses the radiation signal significantly and is included in the analysis. The experiment was performed at the UCLA Pegasus photoinjector laboratory. The measurement results show bunches of sub-40 fs with 2 pC of charge well consistent with the simulation using actual experimental conditions. These results open the way to the generation of ultrashort bunches with time-duration below 10 fs once some of the limitations of the setup (rf phase jitter, amplitude instability and low field in the gun limited by breakdown) are corrected.

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Collimated Fast Electron Emission from Long Wires Irradiated by Intense Femtosecond Laser Pulses

Cited by 29 publications

References 19 publications

Dissipation range turbulent cascades in plasmas

Dissipation range turbulent cascades in plasmas

Strong sub-terahertz surface waves generated on a metal wire by high-intensity laser pulses

Generation and measurement of velocity bunched ultrashort bunch of pC charge

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