Numerical Computation of WavePlasma Interactions in Multidimensional Systems

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Numerical Computation of Wave-Plasma Interactions
in Multi-dimensional Systems
D.B. Batchelor, L.A. Berry, M.D. Carter, E.F.
Jaeger, E. DAzevedo, L. Gray, T. Kaplan
C.K. Phillips, R. Dumont
R.W. Harvey
D.N. Smithe
Lodestar Research Corporation D.A. DIppolito, J.
Myra
P.T. Bonoli J.C. Wright
Visit our web site at http//www.ornl.gov/fed/scid
acrf
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Goal

• Obtain quantitatively accurate, predictive
  understanding of electromagnetic wave processes
  that support important heating, current drive,
  and stability and transport applications in
  fusion-relevant plasmas

In non-uniform plasmamodes can couple
TeraScale Supercomputers are providing access to
new plasma wave physics
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Massively - Parallel Computers Provide Access to
New Plasma Wave Physics

• Higher dimensionality - Computation of important
  wave features in 2-D and 3-D
• Higher resolution - Power to resolve short
  wavelength structures arising from mode
  conversion, high dielectric constant or
  multi-wave interference effects
• Improved calculation of wave driven plasma
  currents resulting from the ability to represent
  arbitrary, non-maxwellian distributions retain
  high cyclotron harmonics include non-local and
  non-linear effects in the conductivity operator
• Inclusion of the effects of non-thermal
  populations on wave propagation and absorption

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Increasing Resolution Results in Proper Radial
Localization of Mode Converted Wavefields
Nm 15
Nm 511
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Project Overview

• Obtain predictive understanding of
  electromagnetic wave processes in fusion relevant
  plasmas with emphasis on four major physics
  areas
• Effect of plasma inhomogeneity in 2-D and 3-D on
  wave absorption and mode conversion processes.
• Effect of non-Maxwellian (generalized) velocity
  space particle distributions on local wave
  absorption, momentum generation, and
  instabilities.
• Application of full-wave solvers to ultra-short
  wavelength regimes (e.g. lower hybrid waves).
• Effect of global plasma modes on wave fields
  produced by launching structures (antennas).

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Computational and Mathematical Challenges

• High dimensionality p.d.e. in 2D or 3D for
  wave fields, up to 5D for distribution function
• ? Large numbers of unknowns 105 ? gt106
• Complex medium
• Spatially non-uniform
• Anisotropic
• Non-local local plasma current is an integral
  operator over EM field at other locations at
  earlier times
• ? Use of spectral representations
• Wide range of length scales involved
  l L ? l ltlt Llength scales can
  interact in localized plasma regions ? mode
  conversion
• ? Need for adaptive (but spectral)
  representation
• Variety of physics mechanisms for absorption
• Non-linearity waves modify plasma on slow time
  scale, non-linear effects on waves
• Basic equations are non-symmetric and dissipative

QPS Compact Stellarator
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Collaborative Research Supported by DOEOffice of
Fusion Energy Science and Office of Advanced
Scientific Computing Research are Resulting in
the Achievement of Physics Goals

• Implementation of 1-D, 2-D, and 3-D full-wave and
  Fokker Planck solvers on massively parallel
  platforms.
• Adaptation of improved serial and parallel
  algorithms for evaluating macroscopic plasma
  responses.
• Reformulating wave-plasma problems and solution
  methods.

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High Resolution (Nm 160 ? 511) is Necessary in
this Mode Conversion Problem to Get The Physics
Right Algorithm enhancements and MPP allowed 103
larger problem to be solved (Nm15?511)