Historical Review on the Plasma Based Particle Accelerators Congratulation for opening “Plasma and Space Science Center” Yasushi Nishida Lunghwa University of Science and Technology, Taiwan Utsunomiya University, Japan

１． Introduction ２． Principle of Plasma Based High Energy Particle Accelerators ３． Brief History Depending on Experimental Results and Future Tasks 4 ． Summary and Future Laser Requirements Dr. Koyama AIST Prof. Uesakathe University of Tokyo Prof. Kitagawa GPI Dr. Kando JAEA Dr. Nemoto CRIEPI with many thanks for materials from

1. Introduction

History of High Energy Accelerators July, 2008 Electron synchrotron Synchrocyclotron Electron linac TRISTAN Electron synchrotron Cyclotron Electrostatic accelerator Rectifier type accelerator YEAR BEAM ENERGY (eV)

50-100

cm 1 cm 1 mm Plasma Limit Breakdown Limit Surface Heating Limit Laser Acceleration SLAC Microwave Limit Acceleration Field (V/m) Wave length

2. Principle of Plasma Based High Energy Particle Accelerators

Mechanism of Plasma Based Accelerator Beat wave method was proved by Kitagawa et al. (’93 RAL & UCLA) Plasma Wake Field method was proved by Rosenzweig et al. (ANL), (’90 KEK & Utsunomiya) VpxB Acceleration mechanism was found by Nishida et al.

Laser wakefield was proved by Nakajima, Ogata, Nishida, et al.. (1) Laser Wakefield (Dorchies et al. 1999) 5. Capillary method by B. Cross et al.,1999

3. Brief History Depending on Experimental Results and Future Tasks

Brief history (1) 1.Concept on plasma-laser based high energy particle accelerator was proposed by Tajima & Dawson in The key idea was to excite large amplitude electron plasma waves by using short pulse laser (LWA) in high density plasma. 3.However, there was no such a laser in that era, and beat wave could excite the plasma waves. 4.In 1983 Nishida et al. succeeded to find new acceleration mechanism, later called VpxB acceleration. This was the first and new mechanism observed of high energy acceleration phenomena.

Brief history (2) 5. In 1986, P.Chen et al proposed to use electron bunch to excite the plasma wave (PWA) and this idea was confirmed by Rosenzweig et al.(1988).In 1990, Nakanishi, Ogata, Nishida et al. observed 2-order of magnitude larger energy. 6. In 1992, Kitagawa et al. succeeded in electron acceleration by using BWA (Beat wave Wake field Accel.) method. 7. In 1995, Nakajima et al. succeeded to accelerate electrons up to 100 MeV by using LWA (Laser Wake field Accel.) method. 8. In 1988, Mine, Mourou et al. invented CPA (Chirped Pulse Amplification) method for short pulse laser amplification and was put in practical use around 1995.

J.R. Rosenzweig et al., PRL (1988)

AIST Monoenergetic beam was met in narrow divergence angle. Electron Energy Spectrum including quasi-monoenergetic beam K.Koyama (AIST, Japan)

Results (C.Murphy, IC/RAL) LOA (France) : Charge in [ ] MeV, 500 ± 200 pC. Monoenergetic Electron Spectrum Observed in LWA

Stable electron beam generation with external static magnetic field Experimental Setup The total charge of the accelerated electrons B = 0 B = 0.2 T Electron beam profile 60mm 9 sequential shot images of the electron beam An excellent stability of the electron parameters has been demonstrated. Sep.18, 2007 ; the University of Tokyo

Accelerator is realized ! Monochromatic energy bunch are excited by using Lasers.

SLAC & UCLA LOA

Laser guiding

Ultra-Intense Laser is illuminated into a glass capillary, which accelerates plasma electrons to 100 MeV Y.Kitagawa-Osaka 10 mm0mm A Laser guide Glass capillary Electrons /MeV/str Energy [MeV] 10 mm long 1.2 mm Detection limit Bump PRL Vol.92, No.20 (2004)

Subjects for Developing the Laser Driven Electron Accelerator Electron injection (standing-wave, sharp density gradient) Bunch diagnostics (bunch length, charge, energy spectrum) Laser guide (capillary, plasma channel) Acceleration scheme, Scaling law (wakefield, beatwave) Application of the laser-plasma accelerator (pump and probe) Laser system for the laser-plasma accelerator (stability, rep-rate, cost) KEK, ILE-Osaka U.Tokyo, AIST, GPI, CRIEPI U.Tokyo, AISTJAEA, U.Tokyo, AIST The UK-Japan High Energy Density Science Workshop, Tokyo, 18-19, Sep K.Koyama, AIST

SLAC, UCLA, USC

4. Summary and Future Laser Requirements Accelerator concepts are reviewed. Laser particle acceleration has been demonstrated. ・ Energy gains at 1 MeV to 200 MeV ・ E-field of 1 GeV/m to 1000 GeV/m ・ GeV energy is expected, although it is realized in PWA Quasi-monoenergetic electron accelerations have been achieved in wide parameter range of self-injection wakefield accelerator. Good pointing stability of electron bunch has been accomplished by applying axial magnetic field. For further higher energy accelerators, the requirements are extreme: ・ Luminosity : 1000 bunches/s with 1 nC/bunch ・ For 1 GeV source 1 PW to 30 PW with kHz range ・ At higher energy, say, 1 TeV source, one need 1 MJ/s or more!! By using PWA, it can reach 1 TeV particles at present, but you need large linear accelerator for accelerating the driver electron bunches.