- description:
Allows loading particles from an SDDS file. This is an alternative to using
a cathode and can provide essentially arbitrary particle distributions.
Since spiffe
is a 2.5 dimensional code, the ``particles'' are really
rings at a given radius and longitudinal position.
- example:
&load_particles
filename = "particles.sdds",
&end
This loads particles from the file particles.sdds
.
- synopsis and defaults:
#namelist load_particles
STRING filename = NULL;
long sample_interval = 1;
double stiffness = 1;
#end
- details:
- filename: Name of the SDDS file from which to take particle data.
The file must have the following columns with the following units:
- z
- : longitudinal position in meters.
- r
- : radial poition in meters. If the particle position is initially
outside the problem region or inside a metal volume, it will move
ballistically until it enters the problem region or emerges from the metal.
- pz
- : longitudinal momentum,
.
- pr
- : radial momentum,
.
- pphi
- : azimuthal momentum,
.
- q
- : charge, in Coulombs.
- sample_interval: Causes
spiffe
to take only every
sample_interval
particle from the file.
- stiffness: Allows making the beam artificially stiff. Equivalent
to increasing the particle mass by the given factor.