Escience grid facility for Europe and Latin America

E-science grid facility for Europe and Latin America Drift Kinetic Equation solver for Grid (DKEs. G) A J. Rubio-Montero 1, L. A. Flores 1, F. Castejón 1, 2, M. Rodríguez-Pascual 1, E. Montes 1 and R. Mayo 1. 1 CIEMAT(Spain) 2 Lab. Nacional de Fusión (Spain) 21 st Intern. Conf. on Numerical Simulation of Plasmas. Lisbon, Portugal. Oct 6 th, 2009. www. eu-eela. eu

Plasma behaviour simulation q High cost of a experimental discharge in a reactor q Complexity of simulating plasmas – Plasma Physics are related to Statistical Physics, Thermodynamics, Fluid, Kinetic and Chaos Theories. – 1 ms of complete simulation = several days in a 50 -100 TFlops machine like Mare Nostrum q Mathematical methods suitable to run on distributed environments as Langevin and Fokker-Plank equations, Monte Carlo, are used to solve: – Plasma-wall interaction They could take advantage from – Neutral particle orbits the large amount of resources – Transport being already in Grid – Massive Ray Tracing – Coil optimization www. eu-eela. eu 21 st Intern. Conf. on Numerical Simulation of Plasmas. Lisbon, Portugal. Oct 6 th, 2009 4

NC transport and DKE solvers q Neoclassical (NC) transport is – a fundamental step of the complete simulation cycle of the behaviour – – of plasmas inside Fusion reactors. caused by magnetic field inhomogeneities and by collisions always present in all Fusion devices (stellarators and 3 D tokamaks). It is a low boundary of total transpport usually used to study the efficiency of a certain coil configuration before it is implemented (i. e. ITER). q NC transport can be simulated by Drift Kinetic Equation (DKE) solvers and Monte Carlo (MC) methods – DKE advantage over MC: can calculate all transport coefficients, MC only can estimate the diagonal ones. – DKE drawback under MC: § high computation time and memory consumption, being usually executed on shared memory computers. § MC methods should be easily deployed on Grid. www. eu-eela. eu 21 st Intern. Conf. on Numerical Simulation of Plasmas. Lisbon, Portugal. Oct 6 th, 2009 5

DKE solver reference code q Variational DKES version (W. I. van Rij & S. P. Hirshman) – Obtain upper and lower bounds for the NC diffusion coefficients of a prescribed toroidal plasma equilibrium. – Widely accepted by the Fusion Community. – Applied to stellarators such as TJ-II, HSX, CHS, LHD, ATF, W 7 -AS; and to projected ones: V 7 -X, NCSX, QPS. – We plan also apply it to 3 D tokamaks like ITER. q Available code – Developed in Fortran 77 in 1989 – Implemented for obsolete shared memory hosts (CRAY-1, CRAY-X-MP) – Modified (~2001) to run on SGI Origin 3000 MIPS machines (IRIX 64). – Parametric and sequential nature www. eu-eela. eu 21 st Intern. Conf. on Numerical Simulation of Plasmas. Lisbon, Portugal. Oct 6 th, 2009 6

How work with Variational DKES q Requires continuously manual configuring, recompiling code and compilation of high number of output data files q Magnetic configuration is described by Fourier series q Energy distribution function of particles by a a series of Legendre polynomials. q Parameter sweep of normalized collisionatillity and electrical field. q Results: only normalized diffusion coefficients (independent of temperature and density). www. eu-eela. eu 21 st Intern. Conf. on Numerical Simulation of Plasmas. Lisbon, Portugal. Oct 6 th, 2009 7

DKEs. G - Objectives New framework: DKEs. G (Drift Kinetic Equation solver for Grids) to q Easily retrieve all neoclassical transport coefficients: q Reducing time execution and increasing precision making use of heterogeneous resources from different Grid infrastructures. q Filling a broad database with the complete [configuration - transport matrix – state] for several Fusion reactors to: – Bring results to Fusion Community – Avoid performing the same simulation twice and easy re-analysis q Easy interaction with other Fusion applications to build complex workflows to – Perform complete simulations of plasma – Find more optimized TJ-II configurations www. eu-eela. eu 21 st Intern. Conf. on Numerical Simulation of Plasmas. Lisbon, Portugal. Oct 6 th, 2009 8

Calculus of specific NC coefficients q Diffusion coefficients – Normalized coefficients returned by DKES depends of energy K: – Diffusion of n and T – Bootstrap current – Resistivity enhancement q Transport coefficients Depends of n and T – Need >106 Dij to fit correctly the integral and solve only 1 Lij www. eu-eela. eu 21 st Intern. Conf. on Numerical Simulation of Plasmas. Lisbon, Portugal. Oct 6 th, 2009 9

DKEs. G current status q All code in a nutshell – Algorithms from DKES software up-to date and extended – Ported and optimized to Linux x 86 -32, x 86 -64 and ia-64 platforms – Only a binary per architecture and algorithm – No software must be installed in resources q Grid-enabled: – Automatic generation of input files and unatended submission of jobs to Grid through Grid. Way – Run on Globus and g. Lite Grids – Tested on EGEE-III, EELA-2 and regional infrastructures. q A module to calculate NC transport coefficients has been developed www. eu-eela. eu 21 st Intern. Conf. on Numerical Simulation of Plasmas. Lisbon, Portugal. Oct 6 th, 2009 10

DKES vs. DKEs. G Each DKES 3 instance is submited with its input to Grid Returns : • NC diffsion coefficients for a specific Temperature and density. • 9 element matrix of NC transport coefficients www. eu-eela. eu 21 st Intern. Conf. on Numerical Simulation of Plasmas. Lisbon, Portugal. Oct 6 th, 2009 11

Some results for TJ-II q Applied to TJ-II Flexible Heliac – Sited at CIEMAT Madrid (Spain) – Began fully operational in 1997 – 1. 5 m major plasma radius q DKEs. G Inputs: – Normallized collisionallity [0. 1. . 100] with 0. 5 step – 5 electrostatic potentials (assumed constant on every magnetic surface) – Fixed: 4 cm plasma radius, 100 Legendre, 343 Fourier polynomials – Temperature and atomic mass set to 1. q Total : – 2500 pairs processed within 500 jobs – Distributed among 12 EELA-2 Grid sites. – 1 job ~ 4 mins in a core Xeon 5160(3. 0 Ghz) 500 jobs ~ 33 hours – Total time spent: ~53 mins. – Wallclock: ~ 45 hours (middleware & file transfer overhead not included) www. eu-eela. eu 21 st Intern. Conf. on Numerical Simulation of Plasmas. Lisbon, Portugal. Oct 6 th, 2009 12

Some results for TJ-II q Diffusion of density and temperature Normalized diffusion coefficient by normalized electrical field www. eu-eela. eu NC diffusion coefficient D 11 for T=1 Ke. V and M=1 u 21 st Intern. Conf. on Numerical Simulation of Plasmas. Lisbon, Portugal. Oct 6 th, 2009 13

DKEs. G: Future q High level implementation on java DRMAA standard – Suitable to run on Globus/g. Lite Grids through Grid. Way or on local clusters through PBS, SGE or LSF – Integration in complex application level workflows and databases § VMEC – DKEs. G § FAFNER-2 – DKEs. G § Ma. Ra. Tra – DKEs. G – Independent GUI q Fill coefficients database and offer it as virtual observatory www. eu-eela. eu 21 st Intern. Conf. on Numerical Simulation of Plasmas. Lisbon, Portugal. Oct 6 th, 2009 14

Thanks for you attention ? www. eu-eela. eu 21 st Intern. Conf. on Numerical Simulation of Plasmas. Lisbon, Portugal. Oct 6 th, 2009 15