Observation of the inhomogeneous spatial distribution of MeV ions accelerated by the hydrodynamic ambipolar expansion of clusters

Kanasaki, Masato; Jinno, Satoshi; Sakaki, Hironao; Faenov, A.*; Pikuz, T.*; Nishiuchi, Mamiko; Kiriyama, Hiromitsu; Kando, Masaki; Sugiyama, Akira; Kondo, Kiminori; et al.

Radiation Measurements, 83, p.12 - 14, 2015/12

https://doi.org/10.1016/j.radmeas.2015.06.011

An inhomogeneous spatial distribution of laser accelerated carbon/oxygen ions produced via the hydrodynamic ambipolar expansion of CO clusters has been measured by using CR-39 detectors. An inhomogeneous etch pits spatial distribution has appeared on the etched CR-39 detector installed on the laser propagation direction, while homogeneous ones are appeared on those installed at 45 and 90 from the laser propagation direction. From the range of ions in CR-39 obtained by using the multi-step etching technique, the averaged energies of carbon/oxygen ions for all directions are determined as 0.78 0.09 MeV/n. The number of ions in the laser propagation direction is about 1.5 times larger than those in other directions. The inhomogeneous etch pits spatial distribution in the laser propagation direction could originate from an ion beam collimation and modulation by the effect of electromagnetic structures created in the laser plasma.

High order harmonics from relativistic electron spikes

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T. A.*; Kawachi, Tetsuya; Sagisaka, Akito; et al.

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

https://doi.org/10.1088/1367-2630/16/9/093003

Relativistic high harmonic generation in gas jet targets

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T. A.; Kawachi, Tetsuya; Sagisaka, Akito; et al.

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

https://doi.org/10.1063/1.4737557

Soft-X-ray harmonic comb from relativistic electron spikes

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T. A.; Kawachi, Tetsuya; Sagisaka, Akito; et al.

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

https://doi.org/10.1103/PhysRevLett.108.135004

We demonstrate a new high-order harmonic generation mechanism reaching the "water window" spectral region in experiments with multi-terawatt femtosecond lasers irradiating gas jets. A few hundred harmonic orders are resolved, giving J/sr pulses. Harmonics are collectively emitted by an oscillating electron spike formed at the joint of the boundaries of a cavity and bow wave created by a relativistically self-focusing laser in underdense plasma. The spike sharpness and stability are explained by catastrophe theory. The mechanism is corroborated by particle-in-cell simulations.

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

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T. A.; Koga, J. K.; Kiriyama, Hiromitsu; et al.

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

http://doi.org/10.1117/12.892898

Tomography of an ultrafast laser driven proton source

Ter-Avetisyan, S.*; Schnrer, M.*; Nickles, P. V.*; Sandner, W.*; Borghesi, M.*; Nakamura, Tatsufumi; Mima, Kunioki*

Physics of Plasmas, 17(6), p.063101_1 - 063101_6, 2010/06

https://doi.org/10.1063/1.3428740

Using a multichannel Thomson spectrometer we have implemented a tomographic approach allowing the reconstruction of the emission characteristics of a laser driven proton source with high energy and spatial resolution. The results demonstrate the complexity of the temporal and spatial characteristics of such a source. The emitted proton beam, which is laminar and divergent ant high energies, becomes convergent at low energies. This implies that a fraction of the proton beam having this kinetic energy is emitted in a collimated way from the target at the turning point between these tow behaviors. Only a finite fraction of the target surface is contributing to the ion spectrum, which is measured at a specific angle within the beam cone. Therefore the momentum distribution of the protons in the emitted beam at any point in space can be controlled by determining the proton source area.

Dependence of the ion energy on the parameters of the laser pulse and target in the radiation-pressure-dominated regime of acceleration

Echkina, E. Yu.*; Inovenkov, I. N.*; Esirkepov, T. Zh.; Pegoraro, F.*; Borghesi, M.*; Bulanov, S. V.

Plasma Physics Reports, 36(1), p.15 - 29, 2010/01

https://doi.org/10.1134/S1063780X10010022

Ionography of submicron foils and nanostructures using ion flow generated in fs-laser cluster plasma

Faenov, A. Ya.; Pikuz, T. A.; Pikuz, S. A.*; Fukuda, Yuji; Kando, Masaki; Kotaki, Hideyuki; Homma, Takayuki; Kawase, Keigo; Kameshima, Takashi*; Pirozhkov, A. S.; et al.

Contributions to Plasma Physics, 49(7-8), p.507 - 516, 2009/09

https://doi.org/10.1002/ctpp.200910050

Superthermal and efficient-heating modes in the interaction of a cone target with ultraintense laser light

Nakamura, Hirotaka*; Chrisman, B.*; Tanimoto, Tsuyoshi*; Borghesi, M.*; Kondo, Kiminori; Nakatsutsumi, Motoaki*; Norimatsu, Takayoshi*; Tampo, Motonobu; Tanaka, Kazuo*; Yabuuchi, Toshinori*; et al.

Physical Review Letters, 102(4), p.045009_1 - 045009_4, 2009/01

https://doi.org/10.1103/PhysRevLett.102.045009

Interactions between a relativistic-intensity laser pulse and a cone-wire target are studied by changing the focusing point of the pulse. The pulse, when focused on the sidewall of the cone, produced superthermal electrons with an energy 10 MeV, whereas less energetic electrons 1 MeV were produced by the pulse when focused on the cone tip. Efficient heating of the wire was indicated by significant neutron signals observed when the pulse was focused on the tip. Particle-in-cell simulation results show reduced heating of the wire due to energetic electrons produced by specularly reflected light at the sidewall.

Observation of collisionless shocks in laser-plasma experiments

Romagnani, L.*; Bulanov, S. V.; Borghesi, M.*; Audebert, P.*; Gauthier, J. C.*; Lwenbrck, K.*; Mackinnon, A. J.*; Patel, P.*; Pretzler, G.*; Toncian, T.*; et al.

Physical Review Letters, 101(2), p.025004_1 - 025004_4, 2008/07

https://doi.org/10.1103/PhysRevLett.101.025004