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Kameshima, Takashi; Hong, W.*; Sugiyama, Kiyohiro*; Wen, X.*; Wu, Y.*; Tang, C.*; Zhu, Q.*; Gu, Y.*; Zhang, B.*; Peng, H. S.*; et al.
Applied Physics Express, 1(6), p.066001_1 - 066001_3, 2008/05
A high-quality electron beam with a central energy of 0.56 GeV, an energy spread of 1.2 % rms, and a divergence of 0.59 mrad rms was produced by means of a 4cm ablative-capillary-discharge plasma channel driven by a 3.8 J 27 fs laser pulse. This is the first demonstration of electron acceleration with an ablative capillary discharge where in the capillary is stably operated in vacuum with a simple system triggered by a laser pulse. This result of the generation of a high-quality beam provides the prospects to realize a practical accelerator based on laser-plasma acceleration.
Kameshima, Takashi; Kotaki, Hideyuki; Kando, Masaki; Daito, Izuru; Kawase, Keigo; Fukuda, Yuji; Chen, L. M.*; Homma, Takayuki; Kondo, Shuji; Esirkepov, T. Z.; et al.
no journal, ,
The acceleration method of laser plasma electron acceleration has very strong electric field, however, the acceleration length is veryshort. Hence, the energy gain of electron beams were confined to be approximately 100 MeV. Recently, this problem was solved by using discharge capillary. The feature of plasma was used that high dense plasma has low refractive index. Distributing plasma inside capillary as low dense plasma is in the center of capillary and high dense plasma is in the external side of capillary can make a laser pulse propaget inside capillary with initial focal spot size. Experiments with capillary were performed in China Academy of Engineering Physics (CAEP) and Japan Atomic Energy Agency (JAEA). We obtained the results of 4.4 J laser pulse optical guiding in 4 cm capillary and 0.56 GeV electron production in CAEP in 2006, and 1 J laser pulse optical guiding in 4 cm capillary and electron beams productions.
Kameshima, Takashi; Kotaki, Hideyuki; Kando, Masaki; Daito, Izuru; Kawase, Keigo; Fukuda, Yuji; Chen, L. M.; Faenov, A. Y.; Pikuz, T. A.*; Homma, Takayuki; et al.
no journal, ,
In recent years, It is noted to use of discharge capillary for laser plasma electron acceleration in order to solve the limit owing to laser focal distance. As the higher plasma density is, the lower the refraction index is, laser propagetes into and interacts plasma, keeping its focal size because discharge plasma behaves like optical fiber. This tequnique would make acceleration space much longer, compared to conventional method with several mm length. This time, we measured plasma density profile inside capillary in order to research optimum distribution of the refraction index, which is very important for R&D of capillary. Here, we will talk about the experimental result.
Kameshima, Takashi; Kotaki, Hideyuki; Kando, Masaki; Daito, Izuru; Kawase, Keigo; Fukuda, Yuji; Chen, L. M.; Homma, Takayuki; Kondo, Shuji; Bulanov, S. V.; et al.
no journal, ,
Recently, it is noticed to generate plasma by using capillary discharge in order to solve a limit due to focal distance of laser, which is one of problems in laser plasma electron acceleration. Since the higher its plasma density, the lower plasma refraction index is, a laser propagates in plasma with its focal size kept and interacts plasma in same principle of optical fiber by distributing plasma as its outside is more dense than its inside. In 2006, KEK, JAEA, and Chinese Academy Engineering Physics(CAEP) carried out a collaboration experiment, where we succeed in generating 560MeV electron beam by using discharge capillary. The result will be informed.
