Speaker
Dr
Nicholas Dover
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Description
The behaviour of high power laser driven ion generation at the extreme intensities available at next-generation laser facilities is an important topic for realising potential applications. One of the simplest schemes for proton sources for applications is sheath acceleration, for which different models predict varying dependence on laser and target parameters, motivating experimental investigation.
We will present experimental data investigating sheath driven proton acceleration using the ultra-high intensity, high contrast J-KAREN-P laser. A ~10 J, 40 fs pulse was focused to an intensity ~5x1021 Wcm-2, generating protons up to 50 MeV from freestanding ~μm foils, and up to 40 MeV at 0.1 Hz from a 5 μm tape target, with conversion efficiencies >1% into protons above 10 MeV. Scaling with different methods of laser intensity variation will be discussed. Simultaneous measurement of the electron distribution and optical probing of plasma formation on the rear target surface provide insights into electron absorption. Target irradiation at 45º angle of incidence is shown to produce a systematic asymmetry in rear surface sheath formation and resultant proton distribution due to the non-thermal electron distribution, causing the highest energy protons to be steered partly towards the laser axis.
Primary author
Dr
Nicholas Dover
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Co-authors
Dr
Akira Kon
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Dr
Akito Sagisaka
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Dr
Alexander Pirozhkov
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Prof.
Anatoly Faenov
(Osaka University, Japan and Russian Academy of Sciences, Russia)
Dr
Hiranao Sakaki
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Dr
James Koga
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Dr
Keita Nishitani
(Kyushu University, Japan and National Institutes for Quantum and Radiological Science and Technology, Japan)
Dr
Kiminori Kondo
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Dr
Kiriyama Hiromitsu
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Dr
Koichi Ogura
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Dr
Kotaro Kondo
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Dr
Mamiko Nishiuchi
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Ms
Mariya Alkhimova
(National Research Nuclear University (MEPhI), Russia)
Dr
Masaki Kando
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Mr
Takumi Miyahara
(Kyushu University, Japan and National Institutes for Quantum and Radiological Science and Technology, Japan)
Dr
Tatiana Pikuz
(Osaka University, Japan and Russian Academy of Sciences, Russia)
Dr
Yuji Fukuda
(National Institutes for Quantum and Radiological Science and Technology, Japan)
Prof.
Yukinobu Watanabe
(Kyushu University, Japan)