1. Modeling the benchmark experiments Mingsheng Wei, Fei He, John Pasley, Farhat Beg,… University of California, San Diego Richard Stephens General Atomics Jeremy M. Hill, Linn Van Woerkom, Richard Freeman, … The Ohio State University Fusion Science Center Meeting, January 26-27, 2006, Rochester University of California, San Diego Center for Energy Research

2. outline  Overview - What is the benchmarking experiment all about?  Our resources - access to the available codes, computers and manpower  Three identified benchmark experiments and our modeling approach  Summary

3. Overview  Modeling is descriptive and lack of quantitative comparison to the experiments in the laser solid target interaction. Too many uncertain parameters: laser ASE level, prepulse, … plasma condition (ne, Te, …) Full scale modeling is beyond computational capability! Modeling Experiments — Using simple target geometry — Known laser parameters — Well-characterized plasmas The planned benchmark experiments

4. We have needed codes Personnel: 2 postdocs (full time), 2 project scientists (part-time) Ph.D students at UCSD and OSU Available codes:  Explicit PIC codes for LPI and electron beam productions ( in collaboration with UCLA and UNR) - simulations with realistic electron temperature - feasibility of relative large spatial scale simulations  Hybrid code LSP (with capability of LPI) for beam propagation and energy transport - collisions included - good for high density - suitable for large spatial and long temporal scale Computing facilities:  Super computer at UCSD (TeraGrid IBM cluster, 256 nodes, dual 1.5GHz/node)  OSU Super Computer (BALE Cluster, 50 nodes, dual 1.53 GHz/node)

5. We have developed 3 benchmarking scenarios Near term, already planned:  Electron beam transport in a a nearly 1-D geometry  Electron behavior at the laser plasma interface Future plan:  Electron beam transport in super critical density plasmas

6. Numerical study of electron transport in wire targets High intensity short pulse laser 20 µm cu wire Main diagnosticsPhysics to be studied LSP simulations Electron beam transport Wire target heating Self-generated magnetic fields Ka imaging, HOPG XUV imaging Faraday rotation Proton deflectometry (see Key’s talk) Hot electron propagation property (current density, length, …) Return current heating Magnetic fields Ka yield calculation with MC code ZPW experiment, Feb 2006 (see Pasley’s talk) 1D configuration makes it relative simple to model In addition, explicit PIC simulations will be used for LPI, electron production and transport in wires (Sentoku, UNR)

7. LPI study and behavior of the hot electrons at the interaction interface Main diagnosticsPhysics to be studiedSimulations Reflectometry Ka, HOPG Electron acceleration at critical density surface (explicit PIC) Electron flux injected in the bulk (calculated using MC code) LPI, hot electron production and transport near the interface Small target with tracer layer close to interaction surface Laser incident at a glancing angle ZPW at Sandia, Summer 2006 (see Pasley’s talk) Target small enough to be modeled with PIC codes

8. Electron transport in preformed super critical density plasma targets Main diagnostics Physics to be studied e - beam propagation in super critical density plasmas Propagation instabilities HOPG XUV imaging K a imaging Proton deflectometry Scale length of the filaments as the function of plasma density High intensity shot pulse laser Preformed plasma (10’s n c, 50-80 eV) Thin tracer layer or doped with other materials PIC and hybrid simulations e - beam Well characterized plasma condition provides a good platform for the PIC and hybrid simulations and direct comparison with the experiment.

9. Summary  Benchmarking requires convergence of experiments, diagnostics and modeling  Near term experiments to test two specific aspects - transport - LPI  We have access to appropriate codes modeling such experiments.