Examples

The examples/ directory of the repository contains runnable scripts and input files. Each page below shows the script, explains the physics it sets up and shows the result as produced by the documentation build scripts under docs/scripts/.

• Two-stream instability
• Landau damping
• Langmuir wave
• Bump-on-tail instability
• Weibel instability
• Explicit and implicit schemes
• Gradient of a diagnostic
• Optimising a simulation
• Inferring a parameter from the dynamics
• Timing and scaling

script	what it shows	run time on a laptop CPU
two-stream_instability.py, input.toml	two counter-streaming beams, the default configuration	seconds
Landau_damping.py	damping of a Langmuir wave in a warm plasma	seconds
Langmuir_wave.py	plasma oscillations at the plasma frequency	seconds
bump-on-tail.py, bump-on-tail.toml	four populations, a weak beam on a Maxwellian, explicit or implicit	tens of seconds
Weibel_instability.py	magnetic field generation from a temperature anisotropy	tens of seconds
auto-differentiability.py	gradient of a diagnostic with respect to the drift speed, against finite differences	a minute
optimize_two_stream_saturation.py	minimise the saturated field energy over the ion temperature	minutes
inference_two_stream.py	recover the drift speed from the growth rate with forward-mode derivatives	minutes
scaling_energy_time.py	run time and energy error against resolution	minutes

Run any of them from the repository root, for example

python examples/Landau_damping.py

The scripts open matplotlib windows; set the environment variable MPLBACKEND=Agg to run them without a display.