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Towards a novel laser-driven method of exotic nuclei extraction-acceleration for fundamental physics and technology

西内 満美子*; 榊 泰直*; Esirkepov, T. Zh.*; 西尾 勝久; Pikuz, T. A.*; Faenov, A. Ya.*; Skobelev, I. Yu.*; Orlandi, R.; Pirozhkov, A. S.*; 匂坂 明人*; et al.

Plasma Physics Reports, 42(4), p.327 - 337, 2016/04

 被引用回数:12 パーセンタイル:60.13(Physics, Fluids & Plasmas)

ペタワットレーザーと原子核物理学の技術を組み合わせることで、エキゾチック原子核の性質の測定を決定的に可能にする。数値シミュレーションとレーザー駆動実験により、我々は論文、西内等、Phys. Plasmas 22, 033107 (2015)で提案された「レーザー駆動エキゾチック核抽出-加速法」の展望について紹介する。この方法の特徴は、(1)フェムト秒ペタワットレーザーを、外部イオンビームによって破砕された原子核標的に照射し、(2)そして生成された短寿命の重エキゾチック原子核を数GeVの多価電荷としてまとめて一気に加速する、という画期的な方法である。


High order harmonics from relativistic electron spikes

Pirozhkov, A. S.; 神門 正城; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T. A.*; 河内 哲哉; 匂坂 明人; et al.

New Journal of Physics (Internet), 16(9), p.093003_1 - 093003_30, 2014/09

 被引用回数:30 パーセンタイル:82.18(Physics, Multidisciplinary)

We present a detailed description of our discovery of a new regime of high-order harmonic generation, including experimental data, simulations, and description of new harmonic generation mechanism. The harmonics are generated by multi-terawatt relativistic-irradiance ($$>$$ 10$$^{18}$$ W/cm$$^2$$) femtosecond ($$approx$$ 30-50 fs) lasers focused to gas jet targets. According to our model, the harmonics are produced by sharp, structurally stable, oscillating electron spikes at the joint of boundaries of wake and bow waves excited by the laser pulse.


Mie scattering from submicron-sized CO$$_2$$ clusters formed in a supersonic expansion of a gas mixture

神野 智史; 福田 祐仁; 榊 泰直; 余語 覚文; 金崎 真聡; 近藤 公伯; Faenov, A. Ya.*; Skobelev, I. Yu.*; Pikuz, T.; Boldarev, A. S.*; et al.

Optics Express (Internet), 21(18), p.20656 - 20674, 2013/09

 被引用回数:20 パーセンタイル:72.11(Optics)

三段コニカルノズルを流れる混合ガスジェット中でのクラスター形成に関する数学モデルを提唱した。これを実験的に検証するために、ターゲットからの散乱光の角度分布を測定するミー散乱法を用いてクラスターサイズを評価した。CO$$_2$$(30%)/H$$_2$$(70%)及びCO$$_2$$(10%)/He(90%)混合ガス中に形成されるCO$$_2$$クラスターの平均サイズは、それぞれ0.28$$pm$$ 0.03$$mu$$mと0.26$$pm$$0.04$$mu$$mであった。さらに干渉計を用いることによりガス密度を測定した結果、モデルと2倍以内で一致した。また、ドライネス($=モノマー/(モノマー+クラスター)$比)はモデルを支持する結果であった。このような実験結果により、クラスター形成の数学モデルが混合ガスに対して十分信頼できることが証明された。


Generation of 50-MeV/u He ions in laser-driven ion acceleration with cluster-gas targets

福田 祐仁; 榊 泰直; 金崎 真聡; 余語 覚文; 神野 智史; 反保 元伸*; Faenov, A. Ya.*; Pikuz, T. A.*; 林 由紀雄; 神門 正城; et al.

Proceedings of SPIE, Vol.8779 (Internet), p.87790F_1 - 87790F_7, 2013/05

 被引用回数:0 パーセンタイル:0.05



Characterization of submicron-sized CO$$_2$$ clusters formed with a supersonic expansion of a mixed-gas using a three-staged nozzle

神野 智史; 福田 祐仁; 榊 泰直; 余語 覚文; 金崎 真聡; 近藤 公伯; Faenov, A. Ya.*; Skobelev, I. Yu.*; Pikuz, T.; Boldarev, A. S.*; et al.

Applied Physics Letters, 102(16), p.164103_1 - 164103_4, 2013/04

 被引用回数:25 パーセンタイル:71.79(Physics, Applied)



Identification of high energy ions using backscattered particles in laser-driven ion acceleration with cluster-gas targets

福田 祐仁; 榊 泰直; 金崎 真聡; 余語 覚文; 神野 智史; 反保 元伸; Faenov, A. Ya.*; Pikuz, T.; 林 由紀雄; 神門 正城; et al.

Radiation Measurements, 50, p.92 - 96, 2013/03

 被引用回数:12 パーセンタイル:69.47(Nuclear Science & Technology)



Observations of surface modifications induced by the multiple pulse irradiation using a soft picosecond X-ray laser beam

石野 雅彦; Faenov, A. Ya.*; 田中 桃子; 保 智己*; 長谷川 登; 錦野 将元; Pikuz, T.; 海堀 岳史*; 河内 哲哉

Applied Physics A, 110(1), p.179 - 188, 2013/01

 被引用回数:26 パーセンタイル:72.95(Materials Science, Multidisciplinary)

To study the interactions between the picosecond soft X-ray laser (SXRL) beams and material surfaces, we irradiated the SXRL pulses having a wavelength of 13.9 nm, a duration of 7 ps to Au, Cu, and Si surfaces. Under a single pulse irradiation, the ripple-like structures were formed on the Au and Cu surfaces. These structures were different from the previously investigated conical structures formed on Al surface. And we could confirm that the developments of modified structures, i.e. growth of hillocks, on Au and Cu surfaces were observed under the multiple SXRL pulse exposures. On the Si surface, the deep holes, seemed to be melting structures, induced by the accumulation of multiple pulse irradiations were found. The SXRL beam irradiation on various material surfaces causes the different behaviors of surface modifications, and the changes of surface behaviors are attributed to the differences in elemental properties such as the attenuation lengths of X-ray photons.


X-ray spectroscopy diagnoses of clusters surviving under prepulses of ultra-intense femtosecond laser pulse irradiation

Faenov, A. Ya.*; Skobelev, I. Yu.*; Pikuz, T.; Pikuz, S. A.*; Fortov, V. E.*; 福田 祐仁; 林 由紀雄; Pirozhkov, A. S.; 小瀧 秀行; 下村 拓也; et al.

Laser and Particle Beams, 30(3), p.481 - 488, 2012/09

 被引用回数:8 パーセンタイル:35.32(Physics, Applied)

It is shown that various spectroscopic methods based on measurements of X-ray spectra radiated from cluster targets can be used for estimation of the destruction degree of clusters by laser prepulses. These methods allow answering the important issue of preservation of the dense cluster core at the moment of the arrival of the main laser pulse. In addition, they can be used for quantitative estimation of the size of the undestroyed parts of the clusters and also for measuring the temperature and density of the preplasmas produced by the laser prepulses.


Relativistic high harmonic generation in gas jet targets

Pirozhkov, A. S.; 神門 正城; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T.; 河内 哲哉; 匂坂 明人; et al.

AIP Conference Proceedings 1465, p.167 - 171, 2012/07

 被引用回数:1 パーセンタイル:47.29

We experimentally demonstrate new regime of high-order harmonic generation by relativistic-irradiance lasers in gas jet targets. Bright harmonics with both the odd and even orders are emitted in the forward direction, while the base harmonic frequency is downshifted. The harmonics are generated by linearly as well as circularly polarized pulses. With the 9 TW laser, the harmonics reach 360 eV, within the "water window" spectral region. Using 120 TW laser producing 40 uJ/sr per harmonic at 120 eV, we demonstrate the photon number scalability. The experimentally demonstrated harmonics cannot be explained by previously known mechanisms. We introduce a novel high-order harmonics generation mechanism, which explains our experimental findings.


X-ray emission from relativistically moving electron density cusps

神門 正城; Pirozhkov, A. S.; 中村 龍史; 林 由紀雄; 小瀧 秀行; 川瀬 啓悟*; Esirkepov, T. Z.; 福田 祐仁; 桐山 博光; 岡田 大; et al.

AIP Conference Proceedings 1465, p.159 - 166, 2012/07

 被引用回数:0 パーセンタイル:0.13

We report on novel method to generate ultra-short coherent X-rays using a laser-plasma interaction. Nonlinear interaction of intense laser pulses with plasma creates stable, specific structures such as electron cusps. For example wake waves excited in an underdense plasma by the laser become dense and propagate along with the laser pulse (Flying Mirror). The flying mirror can reflect a counter-propagating laser pulse and directly convert it into high-frequency radiation and compress the pulse. We have conducted experimental results using 9 TW laser with a He gas target. We observed 10$$^{10}$$ photons in the extreme ultra-violet region (12.8-22.0 nm).


Soft-X-ray harmonic comb from relativistic electron spikes

Pirozhkov, A. S.; 神門 正城; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T.; 河内 哲哉; 匂坂 明人; et al.

Physical Review Letters, 108(13), p.135004_1 - 135004_5, 2012/03

 被引用回数:69 パーセンタイル:91.29(Physics, Multidisciplinary)



Coherent X-ray generation in relativistic laser - gas jet interactions

Pirozhkov, A. S.; 神門 正城; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T.; Koga, J. K.; 桐山 博光; et al.

Proceedings of SPIE, Vol.8140, p.81400A_1 - 81400A_16, 2011/10

We present experimental results, theory, and simulations demonstrating two novel sources of coherent X-ray radiation generated in the relativistic laser ($$>$$ 10$$^{18}$$ W/cm$$^{2}$$) interaction with easily accessible, repetitive, and debris-free gas jet targets. The first source, demonstrated with the 9 TW J-KAREN laser (JAEA), is based on a relativistic mirror reflecting a counter-propagating laser pulse. The second source, demonstrated with the laser power ranging from 9 to 170 TW in experiments with the J-KAREN (JAEA) and Astra Gemini (CLF, RAL) lasers, is based on high order harmonics generation by relativistic-irradiance lasers interacting with underdense plasmas.


LiF crystals as high spatial resolution neutron imaging detectors

松林 政仁; Faenov, A. Ya.*; Pikuz, T.*; 福田 祐仁; 加藤 義章*; 安田 良; 飯倉 寛; 野島 健大; 酒井 卓郎

Nuclear Instruments and Methods in Physics Research A, 651(1), p.90 - 94, 2011/09

 被引用回数:7 パーセンタイル:50.42(Instruments & Instrumentation)

中性子ラジオグラフィで標準試料として広く使用されているSensitivity Indicator(SI)をLiF結晶のカラーセンター形成による中性子イメージングに適用した。撮影はJRR-3熱中性子ラジオグラフィ装置において、SIをLiF結晶と中性子イメージングプレート(NIP)とともに直径5mmのピンホールでコリメートした熱中性子ビームに120分間照射することにより行った。過露光となったNIPからの画像読出しには連続繰返し読出し法を適用し、50$$mu$$mの画素サイズで読み出した。一方、LiFの画像は共焦点レーザー顕微鏡を用いて画素サイズ1.38$$mu$$mで読み出した。LiFとNIPにより撮影したSIの中性子透過画像を比較すると、SIのすべてのギャップ(最大250$$mu$$m,最小12.5$$mu$$m)は両者ともにはっきりと確認することができた。ステップの下にある小さな孔については、NIPでは確認できなかった。実験の結果、LiF結晶は中性子イメージング検出器として、高感度,高空間分解能,広いダイナミックレンジ等、優れた特性を有していることが確認できた。


Ablation of insulators under the action of short pulses of X-ray plasma lasers and free-electron lasers

Inogamov, N. A.*; Anisimov, S. I.*; Petrov, Y. V.*; Khokhlov, V. A.*; Zhakhovskii, V. V.*; Faenov, A. Ya.*; Pikuz, T.; Fortov, V. E.*; Skobelev, I. Y.*; 加藤 義章*; et al.

Journal of Optical Technology, 78(8), p.473 - 480, 2011/08

 被引用回数:5 パーセンタイル:29.42(Optics)

An experimental and theoretical study has been carried out of the ablation of a solid insulator with a wide band gap (LiF) under the action of ultrashort laser pulses of the UV range, obtained in a free-electron laser, and the soft X-ray region, obtained in a silver-plasma laser. A comparison is made of the results obtained on the two laser systems. It is shown that the ablation threshold is about the same for both lasers. A theory is presented that explains the weak growth of the ablation mass with increasing surface energy density of the laser radiation (the fluence) in the case of X-ray lasers as a result of the transition from spallation close to the ablation threshold to evaporative ablation at high fluence values.


Two-temperature warm dense matter produced by ultrashort Extreme Vacuum Ultraviolet-Free Electron Laser (EUV-FEL) pulse

Inogamov, N. A.*; Faenov, A. Ya.*; Zhakhovsky, V. V.*; Pikuz, T. A.*; Skobelev, I. Yu.*; Petrov, Y. V.*; Khokhlov, V. A.*; Shepelev, V. V.*; Anisimov, S. I.*; Fortov, V. E.*; et al.

Contributions to Plasma Physics, 51(5), p.419 - 426, 2011/06

 被引用回数:20 パーセンタイル:65.81(Physics, Fluids & Plasmas)



Observation and modeling of high resolution spectral features of the inner-shell X-ray emission produced by 10$$^{-10}$$ contrast femtosecond-pulse laser irradiation of argon clusters

Colgan, J.*; Abdallah, J. Jr.*; Faenov, A. Ya.*; Pikuz, T. A.*; Skobelev, I. Yu.*; 福田 祐仁; 林 由紀雄; Pirozhkov, A. S.; 川瀬 啓悟*; 下村 拓也; et al.

High Energy Density Physics, 7(2), p.77 - 83, 2011/06

 被引用回数:21 パーセンタイル:67.34(Physics, Fluids & Plasmas)



Laser ablation of gold; Experiment and atomistic simulation

Starikov, S. V.*; Stegailov, V. V.*; Norman, G. E.*; Fortov, V. E.*; 石野 雅彦; 田中 桃子; 長谷川 登; 錦野 将元; 大場 俊幸*; 海堀 岳史; et al.

JETP Letters, 93(11), p.642 - 647, 2011/04

 被引用回数:24 パーセンタイル:75.53(Physics, Multidisciplinary)

The interaction of radiation of a picosecond X-ray laser (wavelength $$lambda$$ = 13.9 nm) with targets made of a thick gold film has been studied theoretically and experimentally. It has been shown experimentally that the action of individual X-ray laser pulses with a fluence of $$F$$ $${approx}$$ 21 mJ/cm$$^{2}$$ initiates the nanostructuring of the gold surface. Explicitly taking into account the electron subsystem, we have proposed an atomistic model of ablation that makes it possible to adequately described the experimental results. The atomistic simulation involves the ion-ion potential depending on the electron temperature $$T$$$$_{e}$$. The use of such a potential makes it possible to take into account an increase in the pressure in the system with increasing $$T$$$$_{e}$$ and to reveal two laser ablation mechanisms.


Nanoscale surface modifications and formation of conical structures at aluminum surface induced by single shot exposure of soft X-ray laser pulse

石野 雅彦; Faenov, A. Ya.*; 田中 桃子; 長谷川 登; 錦野 将元; 保 智己*; Pikuz, T. A.*; Inogamov, N. A.*; Zhakhovskii, V. V.*; Skobelev, I. Yu.*; et al.

Journal of Applied Physics, 109(1), p.013504_1 - 013504_6, 2011/01

 被引用回数:33 パーセンタイル:78.14(Physics, Applied)



Spallative ablation of dielectrics by X-ray laser

Inogamov, N. A.*; Zhakhovsky, V. V.*; Faenov, A. Ya.*; Khokhlov, V. A.*; Shepelev, V. V.*; Skobelev, I. Y.*; 加藤 義章*; 田中 桃子; Pikuz, T. A.*; 岸本 牧; et al.

Applied Physics A, 101(1), p.87 - 96, 2010/10

 被引用回数:32 パーセンタイル:76.02(Materials Science, Multidisciplinary)

A short laser pulse in wide range of wavelengths, from infrared to X-ray, disturbs electron-ion equilibrium and increases pressure in a heated layer. The case where the pulse duration $$tau$$$$_{L}$$ is shorter than acoustic relaxation time $$t$$$$_{s}$$ is considered. It is shown that this short pulse may cause thermomechanical phenomena such as spallative ablation regardless of wavelength. While the physics of electron-ion relaxation strongly depends on wavelength and various electron spectra of substances. There are spectra with an energy gap in semiconductors and dielectrics opposed to gapless continuous spectra in metals. The paper describes entire sequence of thermomechanical processes from expansion, nucleation, foaming, and nanostructuring to spallation with particular attention to spallation by X-ray pulse.


Neutron imaging of micron-size structures by color center formation in LiF crystals

松林 政仁; Faenov, A. Ya.*; Pikuz, T.*; 福田 祐仁; 加藤 義章*

Nuclear Instruments and Methods in Physics Research A, 622(3), p.637 - 641, 2010/10

 被引用回数:23 パーセンタイル:83.48(Instruments & Instrumentation)


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