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Session Simulation

uclazyj edited this page Feb 25, 2021 · 3 revisions

Parameter description

"algorithm" : string

The simulation mode. Available modes include "standard" and "popas". The "popas" mode provides the interfaces and emittance/energy spread diagnostics for the beam parameter optimization code developed by ANL.

"nodes" : integer array (2)

The first component define the MPI processors used in each stage (along r-direction); the second component defines the number of pipeline stages used in the simulation (along ξ-direction).

"grid" : integer array (2)

The first and second components define the number of cells used along r- and ξ-direction respectively.

"box" : session

Define the range of the simulation box in r- and ξ-direction. This session includes two parameters:

  • "r" : real array(2) -- Starting and end coordinates in r-direction. Note that the lower limit should be always 0.
  • "z" : real array(2) -- Starting and end coordinates in ξ-direction.

"field_boundary" : string

The boundary condition of fields for the simulation. The current available option is "open".

"max_mode" : integer

The maximum harmonic number of Fourier azimuthal mode.

"interpolation" :: string

The order of interpolation of the simulation. Only "linear" is available currently.

"n0" : real

The plasma density (in the unit of cm-3) for the normalized units. This parameter is required when the ionization is involved.

"time" : real

The length the simulation will run for. Note that the initial time is always zero.

"dt" : real

The time step for pushing the relativistic particle beam.

"nbeams" : integer

Total number of particle beams.

"nspecies" : integer

Total number of plasma species.

"nneutrals" : integer

Total number of neutral gas species.

"dump_restart" : logical

If true, the code will dump the restart files during the simulation.

"ndump_restart" : integer

The frequency of dumping restart files. The program will dump the restart files every ndump_restart steps.

"read_restart" : logical

If true, the code will read the restart files when it starts.

"restart_timestep" : integer

The number at which step the code will start when read_restart is true.

"iter" : integer

The number of predictor-corrector iterations the code will use when solving the plasma response. Setting iter=1 is usually enough for most simulation cases, but it is always good to check with more number of iterations.

"smooth_type" : string

The smoother used to smooth the source terms. The available options include "binomial" and "compensated". Set "none" to switch off the smoother. (The smoother is not working properly now. Please turn it off by setting "none" until this issue is fixed in the future updates.)

"smooth_order" : integer

The order of smooth. It only takes effect for "binomial" and "compensated" types.

"verbose" : integer

This parameter should be always set as 0 unless for debugging purpose. The larger the number is, the more information will be written in the log files. The maximum value is 5.

"random_seed" : integer

Seed of the pseudo-random number generator. Set 0 to use the operating-system-specified seeds, which varies from run to run. Set any integer greater than 0 to use the user-specified seed which is fixed for each run.

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