Computational domain discretization

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In order to solve Maxwell's equations using the finite-difference time-domain method, the computational domain must be discretized.

The computational domain in FDTD++ is currently discretized using a Cartesian mesh with circulating electric and magnetic field components, known as the Yee cell[1]. See the image to the lower right.

Illustration of the Yee cell. JMM: This image shows a left-handed coordinate system -- it needs replacing.

Controlling the discretization

The discretization is controlled entirely by setting the domain disc simulation parameter in the parameters file.

As an example, in order to change the discretization spacings along $x$, $y$, and $z$ to 2 nm (from their default values of 1 nm), the following could be added to the parameters file:

domain disc 2.0e-9

or explicitly set the discretization along each direction:

domain disc 2.0e-9 x
domain disc 2.0e-9 y
domain disc 2.0e-9 z

The latter case also demonstrates how one may modify the discretization along directions non-uniformly.

Notes and references

  1. K. S. Yee, "Numerical solution of initial boundary value problems involving Maxwell's equations in isotropic media," IEEE Trans. Antennas Propagat. 14, 302-307 (1966).