# Center for Computational Physics Developments

## Code 6440

The CCPD is responsible for the development and application of new
computational techniques, algorithms, and diagnostics to problems of
general interest. The primary areas of activity are in computational
gasdynamics, laser plasma interaction, inertial confinement fusion,
applications of Monotonic Lagrangian Grid (MLG) to particle codes,
solar terrestrial interactions, astrophysics, and electromagnetic and
acoustic scattering. Of major interest is the development of
Massively Parallel Processing for Computational Fluid Dynamics and
Computational Physics.

#### Research in Inertial Confinement Fusion

Research is directed to understand the basic physics in the design of
high-gain direct drive Inertial Confinement Fusion (ICF) pellets. In
this concept laser light is used to symmetrically implode a spherical
pellet to sufficiently high densities and temperatures to achieve
thermonuclear fusion. This requires very symmetric illumination and a
stable hydrodynamic implosion. Two- and three-dimensional
state-of-the-art radiation hydrodynamics codes are being developed and
applied study the dynamics of both planar and spherical targets to
provide better understanding of how to control the Rayleigh- Taylor
instability. This project is part of a DOE program in the Plasma
Physics Division where a new 5MJ laser facility with the worlds most
uniform high powered laser has recently been brought on line. The
results of experiments on that facility will be used to benchmark the
codes and provide more confidence in pellet designs.

#### Research in Solar Activity and Heliospheric Dynamics

A major research effort is underway to exploit Massively Parallel
Processing in developing a better understanding of the sun's behavior.
In conjunction with the NASA HPCC program the "Science Grand
Challenge: To understand the solar driving engine, the mechanism of
solar activity and the dynamics of the heliosphere" has been
undertaken. The range of scales necessary to model the sun spans
several orders of magnitude requiring very large 3D numerical
simulation codes using spectral, finite volume, and particle
techniques developed to run on massively parallel computer
systems. Solar activity is the underlying driver for many of the
important phenomena in space physics. Some of the questions that will
be address in this research program are: What photospheric magnetic
and velocity fields lead to solar flares? Are prominence eruptions and
coronal mass ejection due to a loss of equilibrium in a 3D magnetic
field? The answers to these and other questions will help develop a
predictive capability of phenomena having a direct impact on earth.

fig 1. Advanced computer models allow studies of perturbations well
into the nonlinear regime. Simulations show that short (a) and long
(c) wavelengths will not be harmful but intermediate (b) wavelengths
need experimental evaluation.

fig 2. Isosurfaces of (Top) magnetic field magnitude and (bottom)
electric current magnitude illustrating three stages in magnetic flux
tube reconnection from numerical simulations using highly parallelized
Fourier collocation algorithm on the NRL CM5E.

### Other Places to Look

#### Last modified: December 19, 1996

Laboratory for Computational Physics and Computational Physics /
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