Seminar on "Ultra-bright laser-driven sources of MeV particles and radiation using low density foams", 28 April 2022

Seminar of the Laserlab-Europe Expert Group on Laser-driven Inertial Confinement Fusion (ICF/IFE)
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  • When Apr 28, 2022 from 04:00 PM to 05:00 PM (Europe/Berlin / UTC200)
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Speaker: Prof. Dr. Olga Rosmej, GSI Helmholtz Centre for Heavy Ion Research, Darmstadt, Germany


Experiments on the interaction of relativistic laser pulse with pre-ionized low density foam targets were carried out on the PHELIX-facility at GSI, Darmstadt. Experiments and simulations showed a strongly enhanced conversion of laser energy into energy of MeV-particles and radiation. In interaction of ~ 1019 W/cm2 sub-ps laser pulses with pre-ionized foams, high-current beams of direct laser accelerated (DLA) electrons with an effective temperature up to 10× higher than the ponderomotive potential and a charge of 50-100 nC (> 7.5 MeV) were measured [1, 2]. Using foams combined with μm-thin foils or mm-thick high-Z convertors, we successfully demonstrated the generation of ultra-bright bremsstrahlung with photon energies of up to 50-60 MeV and a record-breaking conversion efficiency of 1.4% for photons > 7.5 MeV (giant dipole resonance) [2, 3]; record efficiency of neutron production in gamma-driven nuclear reactions [3]; superintense betatron radiation [4, 5], and strongly enhanced proton acceleration.
The DLA process proved to be very robust and can be used to generate ultra-bright laser-driven sources of particles and photons with energies of tens of MeV already at moderate relativistic laser intensity, which is typical for large kJ-class PW laser facilities used in the ICF research.

1. Rosmej, O.N. et al., “Interaction of relativistically intense laser pulses with long-scale near critical plasmas for optimization of laser based sources of MeV electrons and gamma-rays”, New J. Phys. 21 (2019) 043044
2. O N Rosmej et al, “High-current laser-driven beams of relativistic electrons for high energy density research”, Plasma Phys. Control. Fusion 62 (2020) 115024
3. M. M. Günther et al, Forward-looking insights in laser-generated ultra-intense gamma-ray and neutron sources for nuclear applications and science, Nat Commun 13, 170 (2022)
4. X. F. Shen et al, Bright betatron x-rays generation from picosecond laser interactions with long-scale near critical density plasmas, Appl. Phys. Lett. 118, 134102 (2021)
5. O. N. Rosmej et al, Bright betatron radiation from directlaser-accelerated electrons at moderate relativistic laser intensity, Mat. Radiat. Extremes 6, 048401 (2021)