ALADIN Z-Pinch Model v0.3-QMHD Current-driven plasma stability with Schwinger pair production and quantum pressure effects

Building on the classical/relativistic baseline (v0.2, DOI: 10.5281/zenodo.18306470), this release introduces quantum electrodynamic corrections to the ALADIN pure J₀ Z-pinch model (J₀ = 1.000 × 10¹⁸ A/m²). The invariant stability parameter Π = μ₀ J₀² a² / (ρ c²) = 8 at magnetic–rest-energy equipartition (v_A = c/√2) governs the transition between unstable and potentially stable regimes. QMHD additions: • Faraday-induced axial electric field E_z = −(r/2) dB_z/dt • Crossed-field Schwinger pair production (approximate rate) • Fermi-degenerate quantum pressure from e⁺e⁻ pairs • Effective plasma density ρ_eff,QMHD including pair mass and pressure contributions Simulation results show collapse dynamics, emergent B_z, shear/B_z suppression, and pair density (negligible in this run due to weak induced E_z).