Each source radiates power P outward through an expanding sphere, so the power density at distance r falls with the inverse-square law: doubling the distance cuts the field to a quarter. Independent sources (different antennas, different phases) don't interfere coherently, so their power densities simply add — that's why several weak sources near each other can combine to cross a limit that any one of them alone would not.
S(r) = P / (4·π·r²) [power density, W/m²]
S_total = Σ Sᵢ [incoherent superposition]
E = √(S · Z₀), Z₀ ≈ 377 Ω [equivalent field strength, V/m]
- Tower — highest power, models a cellular base-station antenna.
- Power line — high power at low frequency (50 Hz), models a transmission line's field.
- Appliance — low power, short range, models a router or phone at close distance.
- Safety limit — toggles a highlight where combined power density crosses a representative ICNIRP general-public reference level; the ground heatmap and the glow around each source both derive from the same summed field.
- People / building — accumulate exposure over time as
dose += S · dt at their position; the marker above them shifts from green to red as accumulated dose rises.
The reference level used here is a single illustrative constant, not the exact frequency-dependent ICNIRP table — real limits vary with frequency and source type.