On Aug 14, 2009, at 12:54 PM, [email protected] wrote:
I'd like to simulate magneto-electric materials (etc),
i.e. where D depends on H, and B on E.
As far as I can tell, meep doesn't do this. Would it
be hard to implement?
Meep doesn't currently support this.
The tricky part about implementing such a thing is that the D/E and B/
H fields in FDTD are stored at different times (offset by half a
timestep), so if you want second-order accuracy you need to average
over a couple of timesteps to couple the two fields in this way.
(This is do-able; the easiest way is probaby to save the backup fields
in a copy of the array, which sacrifices memory but avoids having to
modify the curl equations etc....this is important because you want to
avoid a combinatorial explosion of the number of possible cases in the
curl equations.)
Do you need a dispersive version of this, or is nondispersive enough?
(The dispersive materials in Meep are currently among the oldest
unrevised parts of the code, and are a bit messy; I'm hoping to clean
it up for version 1.2 in order to make it easier to implement new
types of dispersive materials.)
How common are real materials that have these properties? (We mostly
work at infrared frequencies in our group, so we don't come across
magnetic materials often.)
Steven
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