src/plasma/formulas.zig is missing, and it is referenced — the library root cannot compile

[gHashTag]

src/plasma/test_values.zig imports formulas.zig, and src/plasma/formulas.zig does not exist. The sibling modules src/qcd/ and src/particle_physics/ both have one; plasma does not.

It is reachable from the library root, so it stops the build:

src/root.zig -> plasma/root.zig -> plasma/test_values.zig -> plasma/formulas.zig  (absent)

And the import is referenced, which is what makes it a fault rather than a dangling name — Zig analyses top-level declarations lazily, so an unused import of a missing file compiles fine. This one is used five times:

const plasma = @import("formulas.zig");
...
const T_fusion = plasma.eVToKelvin(1000.0);
const E_i_hydrogen = 13.6 * plasma.E_CHARGE;
const omega_p = plasma.plasmaFrequency(n_fusion);
plasma.OMEGA_P_TYPICAL_EXP
plasma.errorPercent(omega_p, plasma.OMEGA_P_TYPICAL_EXP)

So the module must export at least: eVToKelvin, E_CHARGE, plasmaFrequency, OMEGA_P_TYPICAL_EXP, errorPercent.

I have not written it, deliberately. Four of those five are standard and unambiguous — E_CHARGE is exact by SI definition, and the plasma frequency has one formula. OMEGA_P_TYPICAL_EXP is an experimental reference value, and inventing a number that another number is then measured against would make the comparison meaningless. That value has to come from whoever knows which experiment it refers to.

CI has been red since 2026-04-19, so this has not been invisible — it has been unread.

Found by tools/check_build_paths.py in gHashTag/trinity, run across nine public Zig repositories. It was the only confirmed fault in the sweep.