Guiding of relativistic electron beams in dense matter by laser-driven magnetostatic fields

Abstract

Intense lasers interacting with dense targets accelerate relativistic electron beams, which transport part of the laser energy into the target depth. However, the overall laser-to-target energy coupling efficiency is impaired by the large divergence of the electron beam, intrinsic to the laser–plasma interaction. Here we demonstrate that an efficient guiding of MeV electrons with about 30 MA current in solid matter is obtained by imposing a laser-driven longitudinal magnetostatic field of 600 T. In the magnetized conditions the transported energy density and the peak background electron temperature at the 60-μm-thick target's rear surface rise by about a factor of five, as unfolded from benchmarked simulations. Such an improvement of energy-density flux through dense matter paves the ground for advances in laser-driven intense sources of energetic particles and radiation, driving matter to extreme temperatures, reaching states relevant for planetary or stellar science as yet inaccessible at the laboratory scale and achieving high-gain laser-driven thermonuclear fusion.

Proton deflectometry of a capacitor coil target along two axes

“…Strong magnetic fields may also be used to guide charged Correspondence to: P. Bradford, York Plasma Institute, Department of Physics, University of York, Heslington, York YO10 5DD, UK. Email: philip.bradford@york.ac.uk particle beams [12] , generate high-power circularly polarized laser pulses [13] , reduce backward stimulated Raman scattering [14] or amplify laser power by magnetized lowfrequency scattering [15] .…”

Transport of kJ-laser-driven relativistic electron beams in cold and shock-heated vitreous carbon and diamond

“…Several methods to guide the REB along its propagation have been proposed. Most of those rely on the collimating effect of MeV electrons via either self-generated [20,[36][37][38][39] or imposed magnetic fields on the kilo-Tesla (kT) range [40,41]. For instance, studies have pointed out that materials with an atomic number greater than Al, that have high heat capacity and ionization level, can yield stable resistive collimation fields over the REB time scale and therefore enhance its collimation [42][43][44].…”

Simple Analysis of the Laser-to-Core Energy Coupling Efficiency with Magnetized Fast Isochoric Laser Heating

“…Magnetic field strengths of 600 -700 T have been achieved using a laser-driven capacitor/coil target [10,11] and a 1.5-ns full-width at half-maximum (FWHM) pulse duration [12,13]. Guiding an REB using such a laserproduced external magnetic field has been experimentally demonstrated in a planar geometry [14].…”