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Single-Point Grounded Condition

The single-point grounded condition is a Dirichlet condition that pins the electric potential to zero at the origin:

\[ \phi(\mathbf{0}) = 0. \]

The condition is gauge-fixing only — it makes the solution unique without biasing the field elsewhere.

When to use this

  • Pure charge-density problems with no ElectricPotentialCondition anywhere on the boundary. Without a single Dirichlet anchor the potential is defined only up to an additive constant and the linear system is singular.
  • Periodic / sector models where every outer boundary is a periodicity or symmetry condition.
  • Open-region simulations truncated with displacement-field conditions on the outer box.

The origin must lie inside the meshed domain. If the origin is outside the domain, use a regular ElectricPotentialCondition on a known node / boundary instead.

Usage

from mufem.electromagnetics.electrostatics import (
    SinglePointGroundedCondition,
)

gauge_bc = SinglePointGroundedCondition(name="Gauge")

electrostatics_model.add_condition(gauge_bc)