@misc{oai:repo.qst.go.jp:00066804,
 author = {ドーバー, ニコラス ピーター and Kevin, Koga James and Nishiuchi, Mamiko and Sakaki, Hironao and Kondo, Kotaro and Fukuda, Yuuji and Kiriyama, Hiromitsu and Miyahara, Takumi and Nishitani, Keita and Ogura, Koichi and Pirozhkov, Alexander and Sagisaka, Akito and Kando, Masaki and Kondo, Kiminori and ドーバー ニコラス ピーター and コーガ ジェームズ and 西内 満美子 and 榊 泰直 and 近藤 康太郎 and 福田 祐仁 and 桐山 博光 and 宮原 巧 and 西谷 勁太 and 小倉 浩一 and ピロジコフ アレキサンダー and 匂坂 明人 and 神門 正城 and 近藤 公伯},
 month = {Apr},
 note = {The behaviour of high power laser-plasma interaction from solid targets, and the resultant ion generation, at the extreme intensities available at state-of-the-art laser facilities is an important topic for realising potential applications. We will present experimental data investigating electron heating and proton acceleration in a sheath field using the ultra-high intensity, high contrast J- KAREN-P laser. Using a 10 J, 40 fs pulse focused to an intensity ~5x1021 Wcm-2 resulted in generation of protons up to 40 MeV at 0.1 Hz from a 5 μm steel tape target. The high repetition rate of the tape target allowed large statistically relevant investigations into the scaling of the electron and proton beam with laser energy, pulse length and spot size.
We demonstrate that the laser accelerated electron temperature depends not only on laser intensity but also on focal-spot size, in which the restriction of the transverse acceleration distance causes saturation of the electron temperature at increasingly small foci. However, the accelerated electron beam profile becomes more collimated and asymmetric with small focal spots. Measurements of the proton beam show only limited benefit to using increasingly small focal spot sizes, and the best scaling for achieving higher maximum proton energies from sheath acceleration is achieved with increasing the pulse energy, rather than reducing the spot size or pulse length., HEDS 2018},
 title = {Experimental investigation of electron heating and proton acceleration scaling to ultra-high intensity pulses},
 year = {2018}
}