| 1. |
- Passoni, Matteo, et al.
(författare)
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Energetic ions at moderate laser intensities using foam-based multi-layered targets
- 2014
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335 .- 1361-6587. ; 56:4, s. 045001-
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Tidskriftsartikel (refereegranskat)abstract
- The experimental feasibility of the laser-driven ion acceleration concept with multi-layered,foam-based targets has been investigated. Targets with the required features have beenproduced and characterized, exploiting the potential of the pulsed laser deposition technique.In the intensity range 1016–1017 Wcm−2, they allow us to obtain maximum proton energies2–3 times higher compared to bare solid targets, able to reach and surpass the MeV range withboth low and ultrahigh contrast pulses. The results of two-dimensional particle-in-cellsimulations, supporting the interpretation of the experimental results, and directions to exploitthe concept also at ultrahigh intensities, are presented.
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| 2. |
- Dieckmann, Mark Eric, et al.
(författare)
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The Weibel instability in a circular rarefaction wave
- 2012
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Ingår i: Proceedings of the 39th European Physical Society Conference & 16th Int. Congress on Plasma Physics. ; , s. P1.176-1-P1.176-4
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Konferensbidrag (refereegranskat)abstract
- Instabilities behind the front of a cylindrically expanding plasma have been investigated experimentally and with a particle-in-cell simulation. Tubelike filamentary structures form behind the front of a plasma created by irradiating wire targets with a ps-duration and intense ( 1019 W cm-2) laser pulse. These filaments exhibit coherent magnetic fields with a remarkable stability ( 103 / wp: plasma frequency). PIC simulations indicate that an instability driven by a thermal anisotropy of the electron population is the cause. This instability requires a plasma density gradient and hot electrons. It can thus contribute to the generation of strongsustained magnetic fields in astrophysical jets.
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| 3. |
- Quinn, K., et al.
(författare)
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Weibel-Induced Filamentation during an Ultrafast Laser-Driven Plasma Expansion
- 2012
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Ingår i: Physical Review Letters. - American Physical Society. - 0031-9007 .- 1079-7114. ; 108:13, s. 135001-
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Tidskriftsartikel (refereegranskat)abstract
- The development of current instabilities behind the front of a cylindrically expanding plasma has been investigated experimentally via proton probing techniques. A multitude of tubelike filamentary structures is observed to form behind the front of a plasma created by irradiating solid-density wire targets with a high-intensity (I∼1019 W/cm2), picosecond-duration laser pulse. These filaments exhibit a remarkable degree of stability, persisting for several tens of picoseconds, and appear to be magnetized over a filament length corresponding to several filament radii. Particle-in-cell simulations indicate that their formation can be attributed to a Weibel instability driven by a thermal anisotropy of the electron population. We suggest that these results may have implications in astrophysical scenarios, particularly concerning the problem of the generation of strong, spatially extended and sustained magnetic fields in astrophysical jets.
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| 4. |
- Sarri, Gianluca, et al.
(författare)
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Dynamics of Self-Generated, Large Amplitude Magnetic Fields Following High-Intensity Laser Matter Interaction
- 2012
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 109:20, s. 205002-
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Tidskriftsartikel (refereegranskat)abstract
- The dynamics of magnetic fields with an amplitude of several tens of megagauss, generated at both sides of a solid target irradiated with a high-intensity (∼1019 W/cm2) picosecond laser pulse, has been spatially and temporally resolved using a proton imaging technique. The amplitude of the magnetic fields is sufficiently large to have a constraining effect on the radial expansion of the plasma sheath at the target surfaces. These results, supported by numerical simulations and simple analytical modeling, may have implications for ion acceleration driven by the plasma sheath at the rear side of the target as well as for the laboratory study of self-collimated high-energy plasma jets.
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