Precision Mapping of Laser-Driven Magnetic Fields and Their Evolution in High-Energy-Density Plasmas

Gao, Lan; Nilson, P. M.; Igumenshchev, I. V.; Haines, M. G.; Froula, D. H.; Betti, R.; Meyerhofer, D. D.

doi:10.1103/physrevlett.114.215003

Cited by 68 publications

(64 citation statements)

References 45 publications

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“…This is possible since the, order 100 T, selfgenerated B-fields (e.g. Biermann battery, ∇n e × ∇T e ) do not influence the plasma anymore as they are confined to high strength [35,36] at < 0.5 mm from the target surface, i.e. over very short scales compared to the typical plasma expansion scale.…”

Section: Historical Contextmentioning

confidence: 99%

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Detailed characterization of laser-produced astrophysically-relevant jets formed via a poloidal magnetic nozzle

Higginson

Revet

Khiar

et al. 2017

High Energy Density Physics

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This manuscript is distributed under a Creative Commons Attribution-NonCommercial-NoDerivs License (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits distribution and reproduction for non-commercial purposes, provided the author and source are cited. General rightsCopyright for the publications made accessible via the Queen's University Belfast Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. AbstractThe collimation of astrophysically-relevant plasma ejecta in the form of narrow jets via a poloidal magnetic field is studied experimentally by irradiating a target situated in a 20 T axial magnetic field with a 40 J, 0.6 ns, 0.7 mm diameter, high-power laser. The dynamics of the plasma shaping by the magnetic field are studied over 70 ns and up to 20 mm from the source by diagnosing the electron density, temperature and optical self-emission. These show that the initial expansion of the plasma is highly magnetized, which leads to the formation of a cavity structure when the kinetic plasma pressure compresses the magnetic field resulting in an oblique shock [A. Ciardi et al., Phys. Rev. Lett. 110, 025002 (2013)]. The resulting poloidal magnetic nozzle generates a standing conical shock that collimates the plasma into a narrow jet [B. Albertazzi et al., Science 346, 325 (2014).]. At distances far from the target, the jet is only marginally magnetized and maintains a high aspect ratio due to its high Mach-number (M ∼ 20) and not due to external magnetic pressure. The formation of the jet is evaluated over a range of laser intensities (10 12 -10 13 W/cm 2 ), target materials and orientations of the magnetic field. Plasma cavity formation is observed in all cases and the viability of long-range jet formation is found to be dependent on the orientation of the magnetic field.

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Section: Historical Contextmentioning

confidence: 99%

“…In Ref. [36] it is clear that the Nerst effect confines the strong self-generated B-fields against the target so that the expanding plasma plume has only low-strength B-fields (i.e. <1 T) that should be negligible compared to the applied (20 T) B-field.…”

Section: Historical Contextmentioning

confidence: 99%

Detailed characterization of laser-produced astrophysically-relevant jets formed via a poloidal magnetic nozzle

Higginson

Revet

Khiar

et al. 2017

High Energy Density Physics

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“…The Biermann mechanism is also the presumed cause of self-generated magnetic fields (of order 10 6 G, β ∼ 1) found in laser-solid interaction experiments [6][7][8] . The laser generates an expanding bubble of plasma by hitting and ionizing a solid foil of metal or plastic.…”

Section: Introductionmentioning

confidence: 99%

The generation of magnetic fields by the Biermann battery and the interplay with the Weibel instability

et al. 2016

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An investigation of magnetic fields generated in an expanding bubble of plasma with misaligned temperature and density gradients (driving the Biermann battery mechanism) is performed. With gradient scales L, largescale magnetic fields are generated by the Biermann battery mechanism with plasma β ∼ 1, as long as L is comparable to the ion inertial length d i . For larger system sizes, L/d e > 100 (where d e is the electron inertial length), the Weibel instability generates magnetic fields of similar magnitude but with wavenumber kd e ≈ 0.2. In both cases, the growth and saturation of these fields have a weak dependence on mass ratio m i /m e , indicating electron mediated physics. A scan in system size is performed at m i /m e = 2000, showing agreement with previous results with m i /m e = 25. In addition, the instability found at large system sizes is quantitatively demonstrated to be the Weibel instability. Furthermore, magnetic and electric energy spectra at scales below the electron Larmor radius are found to exhibit power law behavior with spectral indices −16/3 and −4/3, respectively.

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“…While improvements to stability, energy, and bandwidth must be made before laser-driven ion beams become a practical source for accelerator or biomedical applications, proton radiography is routinely implemented as a diagnostic tool on high energy, high power laser systems throughout the world. Ultrafast TNSA beams of protons have been instrumental in measuring a number of high energy density (HED) electromagnetic phenomena including laser-driven magnetic field generation [15,16], Weibel-type filamentation and magnetic self-organization [17,18], high power laser channeling [19], and laboratory magnetic reconnection [20][21][22]. Compared to D 3 He fusion, an alternate HED radiography source which produces mono-energetic protons, the ultrafast proton beams provide improved spatial resolution due to the small virtual source [7,23] and the quasi-Maxwellian energy spectrum can be employed to achieve temporal resolution by allowing for time-of-flight dispersion of protons before reaching the radiography subject.…”

Section: Introductionmentioning

confidence: 99%

Proton beam emittance growth in multipicosecond laser-solid interactions

et al. 2019

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High intensity laser-solid interactions can accelerate high energy, low emittance proton beams via the target normal sheath acceleration (TNSA) mechanism. Such beams are useful for a number of applications, including time-resolved proton radiography for basic plasma and high energy density physics studies. In experiments using the OMEGA EP laser system, we perform the first measurements of TNSA proton beams generated by up to 100 ps, kilojoule-class laser pulses with relativistic intensities. By systematically varying the laser pulse duration, we measure degradation of the accelerated proton beam quality as the pulse length increases. Two dimensional particle-in-cell simulations and simple scaling arguments suggest that ion motion during the rise time of the longer pulses leads to extended preformed plasma expansion from the rear target surface and strong filamentary field structures which can deflect ions away from uniform trajectories and therefore lead to large emittance growth.

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Precision Mapping of Laser-Driven Magnetic Fields and Their Evolution in High-Energy-Density Plasmas

Cited by 68 publications

References 45 publications

Detailed characterization of laser-produced astrophysically-relevant jets formed via a poloidal magnetic nozzle

Detailed characterization of laser-produced astrophysically-relevant jets formed via a poloidal magnetic nozzle

The generation of magnetic fields by the Biermann battery and the interplay with the Weibel instability

Proton beam emittance growth in multipicosecond laser-solid interactions

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