Manipulation of laser-generated energetic proton spectra in near critical density plasma

Palmer, C. A. J.; Dover, N. P.; Pogorelsky, Igor; Streeter, Matthew; Najmudin, Z.

doi:10.1017/s0022377814000798

Cited by 5 publications

(7 citation statements)

References 30 publications

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“…It has been observed that long density gradients in hydrogen plasmas lead to the production of broadband shock accelerated ion beams, while steeper gradients allow for the generation of quasimonoenergetic beams as explained in Refs. [17,23].…”

Section: Physical Modellingmentioning

confidence: 99%

Hydrodynamic computational modelling and simulations of collisional shock waves in gas jet targets

Passalidis

Ettlinger

Hicks

et al. 2020

High Pow Laser Sci Eng

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We study the optimization of collisionless shock acceleration of ions based on hydrodynamic modelling and simulations of collisional shock waves in gaseous targets. The models correspond to the specifications required for experiments with the $\text{CO}_{2}$ laser at the Accelerator Test Facility at Brookhaven National Laboratory and the Vulcan Petawatt system at Rutherford Appleton Laboratory. In both cases, a laser prepulse is simulated to interact with hydrogen gas jet targets. It is demonstrated that by controlling the pulse energy, the deposition position and the backing pressure, a blast wave suitable for generating nearly monoenergetic ion beams can be formed. Depending on the energy absorbed and the deposition position, an optimal temporal window can be determined for the acceleration considering both the necessary overdense state of plasma and the required short scale lengths for monoenergetic ion beam production.

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Section: Physical Modellingmentioning

confidence: 99%

Hydrodynamic computational modelling and simulations of collisional shock waves in gas jet targets

Passalidis

Ettlinger

Hicks

et al. 2020

High Pow Laser Sci Eng

Self Cite

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“…Steeper density gradients allow stronger localised energy deposition and can enhance shockwave generation (Palmer et al. 2014; Tresca et al. 2015).…”

Section: Modelling Of Prepulse-driven Blast Wavesmentioning

confidence: 99%

“…Recent breakthroughs with CO 2 laser technology have allowed the isolation of a single intense pulse, permitting more control over the laser-plasma interaction (Polyanskiy et al 2011). However, typical gas-jet targets have linear or parabolic density scale-lengths 100 µm, too long for the production of quasi-monoenergetic ion beams (Palmer et al 2014).…”

Section: N P Dover and Othersmentioning

confidence: 99%

“…For applications to laser-driven shockwave acceleration of ions, a key quantity is the scale-length between the vacuum region and critical density surface. Steeper density gradients allow stronger localised energy deposition and can enhance shockwave generation (Palmer et al 2014;Tresca et al 2015). To achieve a steep vacuum-plasma interface, a blast wave can be generated in the gas target close enough to the gas-jet edge that the shock expands into the vacuum region.…”

Section: Modelling Of Prepulse-driven Blast Wavesmentioning

confidence: 99%

“…However, typical gas-jet targets have linear or parabolic density scale-lengths , too long for the production of quasi-monoenergetic ion beams (Palmer et al. 2014).…”

Section: Introductionmentioning

confidence: 99%

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Optical shaping of gas targets for laser–plasma ion sources

et al. 2016

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We report on the experimental demonstration of a technique to generate steep density gradients in gas-jet targets of interest to laser-plasma ion acceleration. By using an intentional low-energy prepulse, we generated a hydrodynamic blast wave in the gas to shape the target prior to the arrival of an intense CO 2 (λ ≈ 10 µm) drive pulse. This technique has been recently shown to facilitate the generation of ion beams by shockwave acceleration (Tresca et al., Phys. Rev. Lett., vol. 115 (9), 2015, 094802). Here, we discuss and introduce a model to understand the generation of these blast waves and discuss in depth the experimental realisation of the technique, supported by hydrodynamics simulations. With appropriate prepulse energy and timing, this blast wave can generate steepened density gradients as short as l ≈ 20 µm (1/e), opening up new possibilities for laser-plasma studies with near-critical gaseous targets.

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Over-critical sharp-gradient plasma slab produced by the collision of laser-induced blast-waves in a gas jet: Application to high-energy proton acceleration

et al. 2021

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Generating thin and high density plasma slabs at a high repetition rate is a key issue for ultra-high intensity laser applications, such as plasma photonics, electron acceleration by few laser-cycle pulses, or collisionless shock acceleration of protons to high energies. In this paper, we present a scheme to generate such plasma slabs. It is based on the propagation and collision in a gas jet of two counter-propagating blast waves (BWs). Each BW is launched by a sudden and local heating induced by a nanosecond laser beam that propagates along the side of the jet. The resulting cylindrical BW expands perpendicular to the beam. The shock front, which is bent by the gas jet density gradient, pushes and compresses the plasma toward the jet center. By using two parallel ns laser beams, one on each side of the gas jet, this scheme enables us to tailor independently two opposite sides of the jet, while avoiding the damage risks associated with counterpropagating laser beams. A parametric study is performed using two and three dimensional hydrodynamic (single fluid), as well as kinetic (Fokker–Planck), simulations. This study shows that the BW bending combined with the collision in a stagnation regime increases the density by more than ten times and generates a very thin (down to few micrometers), near to over-critical plasma slab with a high density contrast (>100) and a lifetime of a few hundred picoseconds. Two dimensional particle-in-cell simulations are, then, used to study the influence of the plasma tailoring on proton acceleration by a high-intensity sub-picosecond laser pulse. It is shown that tailoring the plasma, not only at the entrance but also at the exit side of the picosecond-pulse, enhances the proton beam collimation and increases significantly the number of high energy protons, and their maximum energy.

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Manipulation of laser-generated energetic proton spectra in near critical density plasma

Cited by 5 publications

References 30 publications

Hydrodynamic computational modelling and simulations of collisional shock waves in gas jet targets

Hydrodynamic computational modelling and simulations of collisional shock waves in gas jet targets

Optical shaping of gas targets for laser–plasma ion sources

Over-critical sharp-gradient plasma slab produced by the collision of laser-induced blast-waves in a gas jet: Application to high-energy proton acceleration

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