Hello,
The sources in Meep are current sources. Even if they are named Ex, Hx,
..., what is meant are electric and magnetic currents.
See the following quote from the Meep documentation
(https://meep.readthedocs.io/en/latest/Python_User_Interface/#source):
source
The |source| class is used to specify the current sources via the
|sources| input variable.
...
*Important note*: These are /current/ sources (*J* terms in Maxwell's
equations), even though they are labelled by electric/magnetic field
components. They do /not/ specify a particular electric/magnetic field
which would be what is called a "hard" source in the FDTD literature.
There is no fixed relationship between the current source and the
resulting field amplitudes; it depends on the surrounding geometry, as
described in the FAQ
<https://meep.readthedocs.io/en/latest/FAQ#how-does-the-current-amplitude-relate-to-the-resulting-field-amplitude>
and in Section 4.4 ("Currents and Fields: The Local Density of
States") in Chapter 4 <http://arxiv.org/abs/arXiv:1301.5366>
("Electromagnetic Wave Source Conditions") of the book Advances in
FDTD Computational Electrodynamics: Photonics and Nanotechnology
<https://www.amazon.com/Advances-FDTD-Computational-Electrodynamics-Nanotechnology/dp/1608071707>.
Cheers,
Thomas
On 03-May-18 18:28, KOHLMANN Hannes wrote:
Hello,
I want to simulate the propagation effects of EM waves generated by a
lightning stroke, for which usually an I(z,t) is given (lightning
channel current).
Is there any way to tell PyMeep that the source is a current I (and
not Ex, Hx, etc)?
If not, then I think the only way to find something descriptive for
the lightning channel would be to calculate the corresponding
Hy and use this as a source, right?
Also, for a custom function, I guess I will need meep.CustomSource and
the src_func as parameter. But I haven’t figured out yet how put those
parameters together, because I haven’t found any example (maybe I have
overseen something in the docs). Could you give me a short one, please?
Thanks in advance!
Best regards,
Hannes
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