Modeling of subchannel formation in laser-assisted capillary discharges (Conference Presentation)

Capillary discharges are widely used in many experiments devoted to laser-plasma interaction as a simple tool to create plasma with required parameters. One of the application of these experiments is laser-plasma accelerators (LPA) of charged particles. Such LPAs are able to accelerate electrons bunch to more that a GeV on the centimeters distances [1]. Essential part of these experiments is capillary discharge. It is used to create plasma waveguide in order to channel an accelerating laser pulse. The long (several decimetres) and thin (several microns) capillary is needed to achieve maximum acceleration but its fabrication is laborious and unreasonably expensive for the LPA experiments. Also capillary can be damaged by electric current pulse that is used to create plasma waveguide. Additional heating of the plasma channel by a nanosecond laser pulse is used in order to avoid these limitations [2]. Propagation of a heater laser through the plasma waveguide deepens it further in the vicinity of the capillary axis. Recent experiments show positive effect of such heating on the final acceleration of the electrons. This leads to a problem of choosing optimal parameters to achieve maximal acceleration. Consistent numerical modeling of plasmadynamics and laser pulse propagation in plasma channel is required to maintenance and optimise the future experiments. The magnetohydrodynamic (MHD) code MARPLE [3] previously used for discharge simulations [3-5] was improved by taken into account additional heating due to laser radiation. Results of simulations that were done for the BELLA experimental facility will be presented at the conference. The work was supported in part by the Competitiveness Program of MEPhI No.02.A03.21.0005, basic research program of the Project 3-OMN RAS, U.S. DOE under Contract No.DE-AC02-05CH11231, EU Reg.Dev.Fund Ns.CZ.02.1.01/0.0/0.0/15 008/0000162 and CZ.02.1.01/0.0/0.0/15_003/0000449 and by the MoEYaS of the Czech Republic No.LQ1606. [1] W.Leemans et al. Phys. Rev. Lett. 113, 245002 (2014) [2] N.Bobrova et al. Phys. Plasmas 20, 020703 (2013) [3] G.Bagdasarov et al. Phys. Plasmas 24, 053111 (2017) [4] G.Bagdasarov et al. Phys. Plasmas 24, 083109 (2017) [5] G.Bagdasarov et al. Phys. Plasmas 24, 123120 (2017)