Cluster Emission Models

Source implementations are in src/pam/2d/sources.jl and src/pam/3d/sources3d.jl.

Bubble Cluster

For squiggle and network activity, generated bubble clusters emit a tapered harmonic signal:

\[s(t) = A \cdot w_\mathrm{Tukey}(t; T_\mathrm{gate}, r) \cdot \sum_{n \in H} \alpha_n \cos(2\pi n f_0 t + \phi_n)\]

The signal is active during the configured gate and zero outside it.

Symbol	Field	2D default	3D default
`f0`	`fundamental`	500 kHz	500 kHz
`A`	`amplitude`	1.0	1.0
`H`	`harmonics`	`{2, 3}`	`{2, 3, 4}`
`alpha_n`	`harmonic_amplitudes`	`[1.0, 0.6]`	`[1.0, 0.6, 0.3]`
`phi_n`	`harmonic_phases`	`[0.0, 0.0]`	`[0.0, 0.0, 0.0]`
`T_gate`	`gate_duration`	50 us	50 us
`r`	`taper_ratio`	0.25	0.25

Term	Meaning
`t`	Time measured from source onset after subtracting source delay.
`f0`	Fundamental emission frequency; harmonics are integer multiples of it.
`n`	Harmonic order.
`A`	Cluster pressure amplitude on a linear scale.
`alpha_n`	Relative amplitude of harmonic `n`.
`phi_n`	Phase of harmonic `n`, set by the selected phase mode.
`T_gate`	Total emission duration.
`w_Tukey`	Tapered rectangular window. `r=0` is rectangular; `r=1` is Hann-like.