Laser-driven quasimonoenergetic proton burst from water spray target

A narrow band proton bursts at energies of 1.6±0.08 MeV were observed when a water spray consisting of ∅(150 nm)-diameter droplets was irradiated by an ultrashort laser pulse of about 45 fs duration and at an intensity of 5×1019 W/cm2. The results are explained by a Coulomb explosion of sub-laser-wavelength droplets composed of two ion species. The laser prepulse plays an important role. By pre-evaporation of the droplets, its diameter is reduced so that the main pulse can interact with a smaller droplet, and this remaining bulk can be ionized to high states. In the case of water, the mixture of quite differently charged ions establishes an “iso-Coulomb-potential” during the droplet explosion such that protons are accelerated to a peak energy with a narrow energy spread. The model explains this crucial point, which differs critically from usual Coulomb explosion or ion sheath acceleration mechanisms.

[1]  S. G. Bochkarev,et al.  Ion acceleration in short-laser-pulse interaction with solid foils , 2005 .

[2]  Michael D. Perry,et al.  Electron, photon, and ion beams from the relativistic interaction of Petawatt laser pulses with solid targets , 2000 .

[3]  Andrea Macchi,et al.  "Light sail" acceleration reexamined. , 2009, Physical review letters.

[4]  O Willi,et al.  Dynamics of electric fields driving the laser acceleration of multi-MeV protons. , 2005, Physical review letters.

[5]  K Mima,et al.  Proposed double-layer target for the generation of high-quality laser-accelerated ion beams. , 2002, Physical review letters.

[6]  S. V. Bulanov,et al.  Fast Ion Generation by High-Intensity Laser Irradiation of Solid Targets and Applications , 2006 .

[7]  Masakatsu Murakami,et al.  Nanocluster explosions and quasimonoenergetic spectra by homogeneously distributed impurity ions , 2008 .

[8]  Patrick Audebert,et al.  Ultrafast Laser-Driven Microlens to Focus and Energy-Select Mega-Electron Volt Protons , 2006, Science.

[9]  D Kiefer,et al.  Radiation-pressure acceleration of ion beams driven by circularly polarized laser pulses. , 2009, Physical review letters.

[10]  Vladimir T. Tikhonchuk,et al.  Quasi-mono-energetic ion acceleration from a homogeneous composite target by an intense laser pulse , 2006 .

[11]  V. F. Kovalev,et al.  Coulomb explosion of a cluster with a complex ion composition , 2008 .

[12]  Masakatsu Murakami,et al.  High energy ions generated by laser driven Coulomb explosion of cluster , 2001 .

[13]  K. Flippo,et al.  Laser acceleration of quasi-monoenergetic MeV ion beams , 2006, Nature.

[14]  K. Mima,et al.  Efficient generation of quasimonoenergetic ions by Coulomb explosions of optimized nanostructured clusters , 2009 .

[15]  T. Tajima,et al.  Laser Electron Accelerator , 1979 .

[16]  P. Nickles,et al.  Time resolved corpuscular diagnostics of plasmas produced with high-intensity femtosecond laser pulses , 2005 .

[17]  M. Murakami,et al.  Self-similar expansion of finite-size non-quasi-neutral plasmas , 2005 .

[18]  Deanna M. Pennington,et al.  Energetic proton generation in ultra-intense laser–solid interactions , 2000 .

[19]  M. D. Perry,et al.  Fast ignition by intense laser-accelerated proton beams. , 2001, Physical review letters.

[20]  Wolfgang Sandner,et al.  First demonstration of collimation and monochromatisation of a laser accelerated proton burst , 2008 .

[21]  Vladimir T. Tikhonchuk,et al.  Laser proton acceleration in a water spray target , 2008 .

[22]  K.-U. Amthor,et al.  Laser-plasma acceleration of quasi-monoenergetic protons from microstructured targets , 2006, Nature.

[23]  T. Sokollik,et al.  Quasimonoenergetic deuteron bursts produced by ultraintense laser pulses. , 2006, Physical review letters.

[24]  T. Sokollik,et al.  Efficient ion acceleration by collective laser-driven electron dynamics with ultra-thin foil targets , 2009, 0909.2334.

[25]  V. F. Kovalev,et al.  Mono-energetic ions from collisionless expansion of spherical multi-species clusters , 2009 .

[26]  S. G. Bochkarev,et al.  Ion acceleration in expanding multispecies plasmas , 2004 .

[27]  Holger Stiel,et al.  A high-density sub-micron liquid spray for laser driven radiation sources , 2003 .

[28]  D. Bauer,et al.  Relativistic attosecond electron bunches from laser-illuminated droplets. , 2009, Physical review letters.