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6.7 Point Sources

Global variable: list PointSources

"Infinitesimal" electric dipole sources (also called Hertzian dipoles) can be simulated in Angora using the PointSources list.

A Hertzian dipole at position $(x_0,y_0,z_0)$ is characterized by the following current distribution in space:


\begin{displaymath}
J(x,y,z;t)={\bf a}\,j_0(t)\,\delta(x-x_0)\delta(y-y_0)\delta(z-z_0)
\end{displaymath}

where $\delta(x)$ is the Dirac delta function. The vector a determines the orientation of the dipole, which can be along the x, y, or z directions. The prefactor $j_0(t)$ is called the current moment of the dipole, with the units (Ampere*m).

Here is an example usage of PointSources:

 
PointSources:
(
    {
        coord_x = 0;
        coord_y = 0;
        coord_z = 0;
        source_orientation = "y_directed";
        waveform_tag = "moment_waveform";
        j_0 = 1.0;
    },
    {
        …
        …
    }
);
Sub-variable of PointSources: floating-point coord_x (units: m)
Sub-variable of PointSources: floating-point coord_y (units: m)
Sub-variable of PointSources: floating-point coord_z (units: m)
Sub-variable of PointSources: integer coord_x_in_cells
Sub-variable of PointSources: integer coord_y_in_cells
Sub-variable of PointSources: integer coord_z_in_cells

These variables specify the Cartesian x, y, and z coordinates of the Hertzian dipole with respect to the grid origin (see section Coordinate Origin). The units are either in meters or grid cells. For the latter, the _in_cells suffix should be appended to the variable name. If the coordinates correspond to non-integer cell positions, the closest integer positions are chosen.

Sub-variable of PointSources: string source_orientation

This string specifies the spatial orientation of the Hertzian dipole. It should be "x_directed", "y_directed", or "z_directed".

Sub-variable of PointSources: string waveform_tag

This string variable specifies the waveform of the current moment $j_0(t)$ . The waveform is interpreted in (Ampere*m) units. This should match a previously-defined tag in a Waveforms definition (see section Waveforms).

Sub-variable of PointSources: floating-point j_0 (units: Ampere/m, default: 1.0)

This is an extra prefactor applied to the current moment waveform $j_0(t)$ .


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This document was generated by Ilker Rafet Capoglu on December 12, 2012 using texi2html 1.82.