py_utils.core.reductions.he_reduction Namespace Reference

Classes
class	HeReductionMode

Detailed Description

core/reductions/he_reduction.py — Helium-occupancy state-space reductions.

Host-independent declaration of the two helium reductions derived in
Ghoniem (2026), Sections 5.2-5.3, as systematic limits of the same
parent master equations.  Both collapse the prohibitive two-dimensional
(m, ell) vacancy-helium grid; they preserve the helium-conservation
moment exactly.

  CASE1_MEANFIELD  (fusion, fast-He equilibration, Section 5.2)
      Helium migrates far faster than cavities grow, so at each vacancy
      size m the loading equilibrates to a mean value mu(m, t).  The 2-D
      grid c_{m,ell} collapses to two 1-D arrays (c_m, Q_m) with
      mu(m) = Q_m / c_m, reducing the vacancy-He block to ~2 N_V ODEs.

  CASE2_DECOUPLED  (fission, decoupled inventory, Section 5.3)
      Helium is a weak perturbation; the per-size loading need not be
      tracked.  A single scalar trapped-He inventory Q_tot is evolved and
      distributed across cavity sizes algebraically by the capture-rate
      weight m^{1/3} c_m.  The vacancy-He block shrinks to N_V + 1 ODEs.

  DYNAMIC
      No reduction: free helium c_h is an explicit ODE variable.  (A
      quasi-steady-state variant solves dc_h/dt = 0 algebraically.)

This module only fixes the taxonomy and the block-count contract; the
size-resolved helium kinetics are supplied by the host material, which
owns the SOLUTE_TRAPPING edge class.