BEACH Documentation

BEACH computes the electric field from charge on triangular surfaces, tracks charged particles in that field, and accumulates the charge of absorbed particles on the surfaces.

Start the ten-minute tutorial · Read the BEACH computation cycle first

Your first 30 minutes

If this is your first use, follow these pages in order. Each page continues from the output of the previous one.

1. Installation — make beach and beachx available.
2. Ten-minute tutorial — follow many particles and surface-charge updates through 20 batches.
3. Inspect output files — read summary.txt and charges.csv.
4. Run and resume — continue the 20-batch result to batch 21.
5. Troubleshooting — separate lint, runtime, output, and restart failures.

The official beginner case is an end-to-end check. A zero exit status does not establish convergence or physical validity. Before using a result for research, follow Validating simulation results.

What BEACH covers

Solved directly by BEACH	Separate models or outside the present scope
Surface charge on each triangle element	A self-consistent volume plasma from charge distributed through space
Fields and potentials from surface charge and configured external fields	Collisional plasma transport outside the computational region
Charged-particle trajectories in a field fixed within each batch	Dielectric polarization or resistive conduction inside an object
Surface absorption, emission, and batch-by-batch charge updates	General secondary-emission and scattering models
An optional quasistatic boundary response at the top of the region	A time-dependent outer sheath or complete velocity-distribution solver

See The BEACH computation cycle for the ordinary surface-charge update and the difference among dt, batch_duration, and batch_count. See quasistatic matching-plane coupling for the spatial division when an outer sheath is attached.

Choose a path

Goal	Reading order
Build a research case	Design a case → Create and validate beach.toml → Run → Validate
Select particle sources or surface models	Choose where particles enter → How surfaces charge
Configure open boundaries and return	Inject particles through a boundary → Particle escape and return
Include photoelectrons	Photoelectron emission and lifecycle
Apply fixed currents from a stationary outer sheath	Zhao stationary closure
Couple an outer one-dimensional sheath	Quasistatic matching-plane coupling → Validate with the offline kinetic oracle
Select field solvers or periodic boundaries	Field evaluation → periodic2 electrostatics
Visualize output	Post-processing tutorial → Python API
Change the source code	Architecture → Development and testing

Documentation structure

Get started

The overview, installation, and first run lead to a 20-batch, multi-particle charging result in which surface charge changes later particle behavior.

Build a case

Choose geometry, particle sources, boundary conditions, and a field solver from the physical goal, then validate, run, and resume the configuration in task order.

Inspect results

Start with a pass/fail check, then visualize, validate numerical and physical behavior, and diagnose failures. Treat successful execution, numerical convergence, and physical validity as separate questions.

Understand the models

These pages explain the ordinary computation cycle, surface charging, particle sources, photoelectrons, open boundaries, the Zhao stationary sheath, periodic2, matching planes, and batch_duration. Read the ordinary path first and open an advanced model only when needed.

Reference

Input parameters, output formats, numerical details, the Python API, and the Fortran API are lookup references, not sequential tutorials.

Developer guide

Start with Architecture, then use Development and testing, Physics release verification, and the generated dependency map.

Canonical ownership

Information	Canonical source
Implemented behavior and invariants	SPEC.md and the Fortran implementation
Input keys, types, and machine validation	schemas/beach.schema.json
Output-file production conditions	schemas/beach.output-manifest.json
Task procedures	Tutorials and user guides on this site
Equations, assumptions, and applicability	The corresponding model or numerical-method page

Potential evolution on an insulating mesh under electron-beam irradiation

_{3D model: Rubber Duck PBR Game Ready (TurboSquid)}