Toshiki Tajima

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Table-top laser wakefield accelerators (LWFAs), proposed theoretically in 1979, have now generated individual electron bunches in the laboratory with a significant number of electrons having energies up to 10 MeV and beyond with the maximum energy reaching tens of MeV and charge per laser pulse of > 1 nC. The attained electron beam properties have(More)
In this article we present the results of particle in cell (PIC) simulations of laser plasma interaction for proton acceleration for radiation therapy treatments. We show that under optimal interaction conditions protons can be accelerated up to relativistic energies of 300 MeV by a petawatt laser field. The proton acceleration is due to the dragging(More)
In this paper we present calculations for the design of a particle selection system for laser-accelerated proton therapy. Laser-accelerated protons coming from a thin high-density foil have broad energy and angular spectra leading to dose distributions that cannot be directly used for therapeutic applications. Our solution to this problem is a compact(More)
Laser acceleration is based on the concept to marshal collective fields that may be induced by laser. In order to exceed the material breakdown field by a large factor, we employ the broken-down matter of plasma. While the generated wakefields resemble with the fields in conventional accelerators in their structure (at least qualitatively), it is their(More)
In order to put the results presented in this thesis into context, a short introduction is given at this point. A brief summary of the experimental results is given on page (iii). The discovery of X-ray radiation has shed light on unexplored territories in almost all disciplines of science, ranging from chemistry, biology, physics, materials science and(More)
A method to generate ultrahigh intense electromagnetic fields is suggested, based on the laser pulse compression, carrier frequency upshift, and focusing by a counterpropagating breaking plasma wave, relativistic flying parabolic mirror. This method allows us to achieve the quantum electrodynamics critical field (Schwinger limit) with present-day laser(More)
Could massive arrays of thousands of fibre lasers be the driving force behind next-generation particle accelerators? The International Coherent Amplification Network project believes so and is currently performing a feasibility study. T he challenge of producing the next generation of particle accelerators, for both fundamental research at laboratories such(More)
ELI has been put on the European Roadmap for Research infrastructures by the European Strategy Forum on Research Infrastructures (ESFRI). It will be the first Paneuropean Infrastructure utilizing an ultra-intense laser with a peak-power of 200 PW for interaction experiments with electric field strength well above the PV/m (10<sup>15</sup> V/m ). With the(More)
We report a high-contrast, high-intensity Ti:sapphire chirped-pulse amplification system that incorporates a nonlinear preamplifier based on optical parametric chirped-pulse amplification (OPCPA). By cooling the Ti:sapphire crystal in the final amplifier down to 77 K, the chirped-pulses are amplified to 2.9 J at a 10 Hz repetition rate without a thermal(More)
Laser wakefield acceleration (LWFA) technology has evolved to where it should be evaluated for its potential as a future competitor to existing technology that produces electron and x-ray beams. The purpose of the present work is to investigate the dosimetric properties of an electron beam that should be achievable using existing LWFA technology, and to(More)