LSP modeling of the electron beam propagation in the nail/wire targets Mingsheng Wei, Andrey Solodov, John Pasley, Farhat Beg and Richard Stephens Center for Energy Research, University of California, San Diego LLE, University of Rochester, General Atomics, San Diego Ti wire Target: - 12 µm kinetic electrons (underdense to critical density) - background solid density Ti(+15) with T initial 100 eV, electrons as the fluid species Grid szie: -  r: µm -  z: µm -Time step: 0.03um Motivations Electron beam propagation and heating of the background plasmas in method 1 - Use LSP hybrid code to simulate large scale plasma that is comparable to the real experiments. - Study the electron beam transport in the nail/wire target - Benchmark code against the experiments * This work is supported by the U.S. Department of Energy under Contract No. DE-FG03-00ER54606, No. DE-FC02-04ER54789, and No. DE-FG02-05ER54834 This work is also partially supported by the National Center for Supercomputing Applications under grant number PHY050034T and utilizes the computer facilities in SDSC. We aim to accurately model the nail/wire experiments Two methods used for modeling the experiment with LSP code Nail target, Cu 2+ plasma, 20μm diameter wire t=0.5ps (pulse center) t=1ps r =0 r =7μm r =10μm FSC  Method 1: Hot electron beam promoted from the background electrons using the empirical scaling  Method 2: Hot electron beam produced from the laser plasma interaction LASER pulse: Gaussian, 0.5 ps (FWHM) energy: 81 J spot size: 16.4 µm (FWHM) intensity: 5  W/cm 2 ELECTRON BEAM conversion efficiency: 30% average energy: T h ~2.23 MeV angular spread: 34  (half-cone angle) 300 µm 50 µm 12 µm underdense plasma kinetic electrons Laser beam launched from the left boundary - Focal spot size: r 0 =7.5 µm - 65 J in the focal spot ps (top hat profile) - I~ 7.36  W/cm 2, a 0 =7.4 Wire target, Cu 2+ plasma, 50 μm diameter wire t=0.5ps (pulse center) t=1ps r =0 r =17μmr =25μm Energetic electron beam production, propagation and heating of the background plasmas in method 2 (preliminary results) That means properly describing the experiment as well as properly simulating the physics Target geometry Laser pulse - including prepulse Properly generate current Analyze in terms of diagnostics Preformed plasma produced by the laser prepulse has been modeled using the 2d rad hydro code h2d. Courtesy of P. Patel at LLNL Initial target position at z=0 Density contour in low  region high  region r=0.9 µm r=7.6 µm r=25 µm B  ~ 25 MG E r ~ 2.5 MV/µm t = 0.5 ps t = 1.0 psc t = 1.4 ps kinetic electron density t = 0.5 ps t = 1.0 ps t = 1.4 ps Background electron temperature  10% of laser energy is transferred to hot electrons which cause significant reduced heating compared to that using the excitation model.  MA current is carried by hot electrons.  Hot electron density drops quickly (by 10 fold) in the first 20 µm.  Strong azimuthal B field and radial E field are generated on the wire surface. Future work:  Simulation for the longer wire case  Including the self-consistent ionization model  Analyze the simulation data in terms of diagnostics used in the experiments t = 1.0 psc Hot electron current vs time