Tatsufumi Nakamura

Demonstration of quasi-monoenergetic electron-beam generation in laser-driven plasma acceleration

The generation of a quasi-monoenergetic electron beam in laser-driven plasma acceleration is reported. A monoenergetic electron beam with an energy of 7 MeV was emitted from a high-density plasma (electron density >1020cm−3) produced by a 2 TW 50 fs laser pulse. The divergence of the monoenergetic beam was ±1.2°. The first Stokes satellite peak of stimulated forward Raman scattering was observed in the spectrum of the light transmitted through the plasma. The plasma wave was excited in the region of which electron density was around 1.3×1020cm−3. The acceleration length was estimated to be 500μm from the length of the side-scattered light image. It is considered that the monoenergetic beam generation is due to the matching of the acceleration length to the dephasing length determined by the velocity difference between the accelerated electrons and the plasma wave.

Stochastic acceleration by intense laser fields

A stochastic acceleration mechanism which is a direct acceleration mechanism effective for the intense laser case is studied by the Fokker–Planck approach. The Fokker–Planck equation of the electron distribution function is derived from the equation of motion of electrons which interact with filamented laser fields. The Fokker–Planck equation contains nonlinear coefficients and gives an anisotropic distribution in momentum space. The strong directionality of the acceleration is explained. The accelerated electrons tend to be collimated towards the direction of the wave vector. The effective temperature scales as T∝tβ with β≃1.

Effects of Laser Wavelength on Hot Electrons Produced by Ultrashort Intense Laser Pulse on Solid-Density Targets

Hot electron temperatures and electron energy spectra in the course of interaction between intense laser pulse and overdense plasmas are reexamined from a viewpoint of the difference in laser wavelength. The hot electron temperature measured by a particle-in-cell simulation is scaled by

Anomalous skin effect for linearly and circularly polarized intense laser light

I

Effect of viscosity on destabilization of the Rayleigh–Taylor instability by thermal conductivity in a fluid

rather than

Dynamics of intense and finite length ion beam propagating in plasma channel

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Analysis of Propagation of an Intense and Short Laser Pulse in Inhomogeneous Plasmas

at the interaction with overdense plasmas with fixed ions, where

Prediction of Hot Electron Production by Ultraintense KrF Laser‐Plasma Interactions on Solid‐Density Targets

I

High energy electron acceleration by stochastic acceleration mechanism

and

Stochastic Analysis of Anomalous Skin Effect for Linearly Polarized Intense Laser Light

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