Extreme ionization of heavy atoms in solid-density plasmas by relativistic second-harmonic laser pulses

Hollinger, R.; Wang, S.; Wang, Y.; Moreau, A.; Capeluto, M. G.; Song, Huanyu; Rockwood, Alex; Bayarsaikhan, E.; Kaymak, Vural; Pukhov, A.; Shlyaptsev, Vyacheslav N.; Rocca, J. J.

doi:10.1038/s41566-020-0666-1

Cited by 35 publications

(15 citation statements)

References 27 publications

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“…It is obvious that the width of the charge-state distributions increases towards thinner targets. The TPS allowed measuring charge states higher than (36 +2 −3 ) + for a foil thickness of 25 nm, while the highest measured charge state is (74 +2 −3 ) + from a 100 nm thick gold foil, which reaches the recently published record ionization value of 72 + , representing the highest charge state of gold that has been observed so far [22]. A significant difference between the charge-state distributions from heated and unheated foils was not observed.…”

Section: Lasermentioning

confidence: 73%

Charge-state resolved laser acceleration of gold ions to beyond 7 MeV/u

Lindner,

Fitzpatrick,

Haffa

et al. 2021

Preprint

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In the past years, the interest in the laser-driven acceleration of heavy ions in the mass range of A ≈ 200 has been increasing due to promising application ideas like the fission-fusion nuclear reaction mechanism, aiming at the production of neutron-rich isotopes relevant for the astrophysical r -process nucleosynthesis. In this paper, we report on the laser acceleration of gold ions to beyond 7 MeV/u, exceeding for the first time an important prerequisite for this nuclear reaction scheme. Moreover, the gold ion charge states have been detected with an unprecedented resolution, which enables the separation of individual charge states up to 4 MeV/u. The recorded charge-state distributions show a remarkable dependency on the target foil thickness and differ from simulations, lacking a straight-forward explanation by the established ionization models.Promising application perspectives for laser-accelerated heavy ions in the mass range of A ≈ 200 led to an awakening interest in laser-based heavy ion acceleration. Since 2015, multiple experimental papers reported on progress in laser-driven acceleration of gold ions, pushing the achieved kinetic energies from 1 MeV/u [1] to 5 MeV/u [2] to finally 6.1 MeV/u [3]. This evolution has been accompanied by several simulations [4-6], which especially studied the expected gold ion charge-state distributions based on the established models of tunnel and electron impact ionization.With this paper, we pursue the long-term goal of realizing the fission-fusion reaction mechanism proposed already a decade ago [7]. This aims at the production of extremely neutron-rich isotopes close to the waiting point of the rapid neutron capture (r -)process at the magic neutron number N = 126 [8], which is a decisive region for the astrophysical nucleosynthesis of the heaviest elements in the Universe. The fission-fusion reaction mechanism is a two-step process, which is expected to be enabled to occur when ultra-dense bunches of laser-accelerated heavy, fissile ions (like 232 Th) with kinetic energies above the fission barrier impinge on a target consisting of the same material. In a first step, both projectile and target ions undergo fission. Afterwards, fusion of fission fragments may happen, in case of fusion between two light fission fragments the desired neutron-rich r -process isotopes are formed. This reaction scheme requires the application of laser-accelerated heavy ion bunches owing to their ultra-high, almost solid-state-like density which is expected when accelerating in the regime of radiation pressure acceleration (RPA) [9][10][11][12]. The densities of ion bunches delivered by conventional accelerators are orders of magnitude lower and thus insufficient to

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Section: Lasermentioning

confidence: 73%

Charge-state resolved laser acceleration of gold ions to beyond 7 MeV/u

Lindner,

Fitzpatrick,

Haffa

et al. 2021

Preprint

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“…Figure 1(e) shows scanning electron microscopy (SEM) image of a typical processed target, where the arrangement of vertical distinct NWs can be observed. In our previous work, the SPD technique was shown to be adequate for producing metal NWs [27,28,34] . However, polyethylene is a very soft material (Young's modulus of LDPE is 200-300 MPa and 600-1500 MPa for HDPE [37] ); it is challenging to obtain a good NW alignment and adequate inter-wire separation over large areas, as the wires tend to bend and bunch, even when using SPD.…”

Section: Nw Array Fabricationmentioning

confidence: 99%

“…This return current gives rise to a nano-pinch effect that compresses the NWs, increasing the local energy density, and altering the NW expansion [31] . At sufficiently high irradiation intensity relativistically induced transparency [32,33] can also aid deep laser penetration even after the inter-wire gaps are filled with an overdense plasma [29,30,34] . For example, at an intensity of 3 × 10 21 W cm -2 the normalized vector potential at λ = 400 nm is a o ∼ 18.7 which implies a relativistic factor γ = 1 + a 2 o /2 of the order of 13.…”

Section: Introductionmentioning

confidence: 99%

Deuterated polyethylene nanowire arrays for high-energy density physics

Capeluto

Curtis

Calvi

et al. 2021

High Pow Laser Sci Eng

Self Cite

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The interaction of intense, ultrashort laser pulses with ordered nanostructure arrays offers a path to the efficient creation of ultra-high-energy density (UHED) matter and the generation of high-energy particles with compact lasers. Irradiation of deuterated nanowires arrays results in a near-solid density environment with extremely high temperatures and large electromagnetic fields in which deuterons are accelerated to multi-megaelectronvolt energies, resulting in deuterium–deuterium (D–D) fusion. Here we focus on the method of fabrication and the characteristics of ordered arrays of deuterated polyethylene nanowires. The irradiation of these array targets with femtosecond pulses of relativistic intensity and joule-level energy creates a micro-scale fusion environment that produced $2\times {10}^6$ neutrons per joule, an increase of about 500 times with respect to flat solid CD2 targets irradiated with the same laser pulses. Irradiation with 8 J laser pulses was measured to generate up to 1.2 × 107 D–D fusion neutrons per shot.

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“…When traversing a spin-polarized target, the pulses form channels similar to magnetic vortex acceleration and eject collimated proton beams. Utilizing particle-in-cell (PIC) simulations we show that the overlapping longitudinal electric fields create an accelerating field beneficial for acceleration that maintains a high spin-polarization even for high field strengths that could be achieved in the future at facilities like ELI and XCELS [21][22][23]. The simulation results are compared to the case of a single beam propagating through the target and the importance of a density downramp at the target's end will be discussed.…”

Section: Introductionmentioning

confidence: 99%

Acceleration of spin-polarized proton beams via two parallel laser pulses

Reichwein¹,

Büscher²,

Pukhov³

2022

Preprint

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We present a setup for highly polarized proton beams using two parallel propagating laser pulses that are polarized in opposite direction. This mechanism is examined utilizing particle-in-cell simulations and compared to a single-pulse setup commonly used for magnetic vortex acceleration. We find that the use of the dual-pulse setup allows for peak energies of 374 MeV and good angular spread for two pulses with normalized laser vector potential a0 = 100. Compared to a single pulse, we further observe better polarization of the obtained bunch.

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Extreme ionization of heavy atoms in solid-density plasmas by relativistic second-harmonic laser pulses

Cited by 35 publications

References 27 publications

Charge-state resolved laser acceleration of gold ions to beyond 7 MeV/u

Charge-state resolved laser acceleration of gold ions to beyond 7 MeV/u

Deuterated polyethylene nanowire arrays for high-energy density physics

Acceleration of spin-polarized proton beams via two parallel laser pulses

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