Magnetized plasma implosion in a snail target driven by a moderate-intensity laser pulse

Abstract

Optical generation of compact magnetized plasma structures is studied in the moderate intensity domain. A sub-ns laser beam irradiated snail-shaped targets with the intensity of about 1016 W/cm2. With a neat optical diagnostics, a sub-megagauss magnetized plasmoid is traced inside the target. On the observed hydrodynamic time scale, the hot plasma formation achieves a theta-pinch-like density and magnetic field distribution, which implodes into the target interior. This simple and elegant plasma magnetization scheme in the moderate-intensity domain is of particular interest for fundamental astrophysical-related studies and for development of future technologies.

Kilotesla plasmoid formation by a trapped relativistic laser beam

“…This probably is the result of stalk grounding, which in the CCWIR target increases electric capacitance. This experiment demonstrates that small "snail" targets driven by high-intensity ps-short laser pulses, generate much stronger quasi-static magnetic fields than bigger targets with longer, sub-ns pulses [26], due to a higher energy density in this regime. Compared to the capacitor-coil targets [15], the snail targets produce stronger magnetic fields but in a smaller volume and for a shorter time.…”

Magnetic field amplification by high power lasers in underdense plasma

“…Experimental benchmarking of this work would benefit from study of the methods employed in [10,11,13], as these experiments are closely related to this work, involving both strong magnetic fields and near-critical plasmas. The plasma density and magnetic fields may be diagnosed via proton deflectometry, polaro-inteferometry [29], Faraday rotation and x-ray phase-contrast imaging.…”

“…In contrast to this, external magnetic fields may be more precisely controlled, and imposed upon a plasma to induce specific effects. Solid-state and conventional electromagnets may be employed up to the order of 100 T [8,9], higher field strengths on the order of 1 kT may be reached by using capacitor-coil targets [10,11] and yet higher fields maybe achieved with so-called snail targets irradiated by intense lasers [12,13]. Such high field regimes offer access to new regimes of physics and applications under unprecedented conditions.…”

Influence of the magnetic field on properties of hot electron emission from ablative plasma produced at laser irradiation of a disc-coil target

“…• Three-frame complex interferometry measuring the spacetime electron density and the SMF distributions in the expanded plasma [22,23], • Four-frame x-ray pinhole camera visualizing the expansion plasma process in the range of the soft x-ray radiation [25], • 2D imaging of the Cu Kα line emission [27] providing information on parameters of the HE emission, namely the total number of photons generated as a result of the interaction of HEs with a copper disc, the energy and laser-to-HE conversion efficiency for HEs deposited in the central hot spot of the targets, the fraction of the HEs deposited outside the central hot spot and • the multi-channel electron magnetic spectrometer [26] measuring the angular characteristics of the HEs emitted outside the Cu discs, i.e. the number of HEs emitted at different angles vs the target normal and angular distributions of their energy and temperature.…”

“…Plasma expands in the axial magnetic field generated by the current flowing in the DC circuit. To investigate the influence of the magnetic field on the parameters of the expanded plasma, the three-frame complex interferometry [22][23][24] and four-frame x-ray camera [25] were implemented in combination with measurements of the HE energy distributions using the multi-channel magnetic spectrometer [26] and 2D imaging of the Cu Kα line emission [27].…”