1 UCLA Plans Warren B. Mori John Tonge Michail Tzoufras University of California at Los Angeles Chuang Ren University of Rochester

Particle models are needed (Rochester MHD Simulation Data) PIC can be used from n c (10 21 cm -3 ) to solid density (10 23 cm -3 )

3 UCLA plan 1. Develop OSIRIS, UPIC, and Dawson Cluster (4.5 Tflops). 2. Use OSIRIS and UPIC to study: a.Absorption of light in both “global” 2D simulations and reduced scale 3D simulations b. Transport of energetic electrons and ions in both “global” 2D simulations and reduced scale 3D simulations 3. Use OSIRIS and UPIC to study collisions: a. Reduce cell size to a fraction of a Debye length to study collisions from first principles (Work with MIT). b. Study finite size particle collisions for in OSIRIS an UPIC(Work with Rochester). Set the stage for asking the validity of fluid theory. 4. Compare full PIC results against LSP (Work with Rochester and Reno) 5. Continue to develop theory for the “Weibel” instabilityrelevant to fast ignition. We are concentrating on collisionless Weibel. (Work with Rochester).

4 UCLA plan UPIC: Task I. Add dynamic load balancing into UPIC Task II. Add open boundary conditions into UPIC. Task III. Add arbitrary initial density function n(x,y,z) profiles into UPIC

5 UCLA plan OSIRIS: Task I. Add open boundary conditions for all directions into OSIRIS. Task II. Add static load balancing into OSIRIS. Task III.Add a “core” region in which energetic particles are absorbed properly. Task IV.Add particle tracking diagnostics.

6 UCLA plan Code comparison: Task I. Working jointly with other Center members, come up with a set of runs for comparing output from the various codes being used across the Center. Task II. Compare results from OSIRIS, UPIC, Reno codes, and LSP on relevant runs.

7 UCLA plan Physics: Task I. Use 2D and 3D simulations to understand the role of return current and the ions on the filamentation of the hot electrons. Task II. Work with experimentalists to prioritize and identify key physics questions that can be studied using PIC.

8 Sample results: Mocking up the core Possible methods: 1.Radial boundary which thermalizes or thermalizes and reflects particles crossing the boundary while maintaining continuity equation. (Implemented -causes large charge build up at boundary) 2.Add position(radial) and velocity dependent drag to particles in core. 3.Add position dependent 2 particle collisions to core (perhaps best solution). Core diagnostics particle energy and direction at the core (in progress)

Parameters for 2D Simulation Ren reference Vacuum region between target and boundary to reduce boundary effects  grids (  x=0.33 c/  p ), with current smoothing, 4 particle/cell 2.4  10 8 particles and 6  10 4 steps Initial T e =7.4keV and T i =1 keV – e /  p   m- laser from left wall antenna, I=10 20 W/cm 2, spot size (FWHM) 7.5  m, 1 ps long, s-&p-polarized. laser coronal plasma

10 Results: half the radius of Ren et al. No core

11 Results: half the radius of Ren et al. Thermalizing core

12 Dawson Cluster 256 node dual processor G5 x-serve cluster 4.5 Tflops Tflops on Linpack With static load balancing, each Ren type run takes 3-4 days on 64 nodes on Dawson

M.Tzoufras, F.S.Tsung, J.W.Tonge, W.B.Mori UCLA C.Ren University of Rochester M.Fiore, L.O. Silva IST (Portugal) Emergence of space charge effects in the linear stage of the Weibel like current filamentary instability