Zoltan Tibai

Intense tera-hertz laser driven proton acceleration in plasmas

We investigate the acceleration of a proton beam driven by intense tera-hertz (THz) laser field from a near critical density hydrogen plasma. Two-dimension-in-space and three-dimension-in-velocity particle-in-cell simulation results show that a relatively long wavelength and an intense THz laser can be employed for proton acceleration to high energies from near critical density plasmas. We adopt here the electromagnetic field in a long wavelength (0.33 THz) regime in contrast to the optical and/or near infrared wavelength regime, which offers distinct advantages due to their long wavelength ( λ=350u2009μm), such as the λ2 scaling of the electron ponderomotive energy. Simulation study delineates the evolution of THz laser field in a near critical plasma reflecting the enhancement in the electric field of laser, which can be of high relevance for staged or post ion acceleration.

Quasi-monoenergetic proton acceleration from cryogenic hydrogen microjet by ultrashort ultraintense laser pulses

Laser-driven proton acceleration from micron-sized cryogenic hydrogen microjet target is investigated using multi-dimensional particle-in-cell simulations. The simulations reproduce well the proton energy spectrum measured at the Titan laser with 700-fs long pulses [23]. High-energy quasi-monoenergetic proton acceleration is predicted in a new regime employing few-cycle (20-fs) ultraintense (2-PW) laser pulses. Weibel-instability influenced collisionless shock wave acceleration mechanism results in a maximum proton energy of as high as 160 MeV and a quasi-monoenergetic peak at 80 MeV for 10^22 W/cm^2 laser intensity and near-solid-density mass-limited targets. A self-generated strong quasi-static magnetic field is also observed in the plasma, which modifies the spatial distribution of the proton beam.

Single-cycle attosecond pulses by Thomson backscattering of terahertz pulses

The generation of single-cycle attosecond pulses based on Thomson scattering of terahertz (THz) pulses is proposed. In the scheme, a high-quality relativistic electron beam, produced by a laser-plasma wakefield accelerator, is sent through suitable magnetic devices to produce ultrathin electron layers for coherent Thomson backscattering of intense THz pulses. According to numerical simulations, single-cycle attosecond pulse generation is possible with up to 1xa0nJ energy. The waveform of the attosecond pulses closely resembles that of the THz pulses. This allows for flexible waveform control of attosecond pulses.

Spatiotemporal focusing dynamics in plasmas at X-ray wavelength

Using a finite curvature beam, we investigate here the spatiotemporal focusing dynamics of a laser pulse in plasmas at X-ray wavelength. We trace the dependence of curvature parameter on the focusing of laser pulse and recognize that the self-focusing in plasma is more intense for the X-ray laser pulse with curved wavefront than with flat wavefront. The simulation results demonstrate that spatiotemporal focusing dynamics in plasmas can be controlled with the appropriate choice of beam-plasma parameters to explore the high intensity effects in X-ray regime.

Generation and Application Possibilities of Terahertz Pulses with Extremely High Field Strength

Generation and application possibilities of terahertz pulses with 10 MV/cm peak electric field strength is discussed. Production of single-cycle or shaped EUV pulses with sub-nJ energy by coherent Thomson-scattering on ultrashort electron bunches is predicted.