Source: Acoustic Input

The source defines how acoustic energy is introduced into the simulation. It forms the third of the four core components that define every k-Wave simulation.

Source Types

Initial Pressure (p0): Initial pressure distribution (e.g., photoacoustic imaging):

source.p0 = initial_pressure_distribution  # Same size as grid

Time-Varying Pressure (p, p_mask): Pressure sources that vary in time (e.g., ultrasound transducers):

source.p_mask = transducer_mask       # Binary mask
source.p = pressure_time_series       # shape: (N_source_points, N_time_steps)

Velocity Sources (ux, uy, uz, u_mask): Particle-velocity sources.

Stress Sources (sxx, syy …): For elastic-wave simulations.

Source Modes

Additive (default): Source terms are added to the field equations.

Dirichlet: Source values are enforced as boundary conditions.

Common Patterns

# Photoacoustic initial pressure
source = kSource()
source.p0 = initial_pressure_distribution

# Ultrasound transducer
source = kSource()
source.p_mask = transducer_mask
source.p = tone_burst_signal  # shape: (N_source_points, N_time_steps)

# Enforce Dirichlet mode explicitly (pressure boundary condition)
source.p_mode = "dirichlet"

For transducer modeling and advanced source configurations, see ../fundamentals/understanding_sources.