Near-field truncation against 120 orders

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Reference
near-field truncation against 120 orders
Kind
precision: the same mathematics in mpmath at 60–80 digits, written separately in src/pystratify/references.py and benchmarks/mp_reference.py: proves the numerics, not the formulation
Calculated
|E|², energy density
Agreement
report
A 50 nm gold-like sphere (n = 0.25 + 3i) in water, 600 nm: |E|² outside it against 120 orders The far-field truncation (Wiscombe's, 5 orders here) is enough for cross sections but not at the surface, where it misses |E|² by 3e-5; regime='near', which the calculator uses for fields, adds the orders the distance needs.
10015020025030035040010⁻¹11010²distance from the centre [nm]|E|²
|E|², PyStratify near-field truncation (11 orders) |E|², 120 orders
Hover to read values.
  • largest relative difference: 6.23×10⁻¹⁵
  • PyStratify the lines, the reference the circles

Run it yourself: figures.py on GitHub, PyStratify 97e52a9