Harmodynamics V: Solar System Constraints and the Chameleon Screening Mechanism

Abstract Previous works in the Harmodynamics series have successfully described galactic rotation curves (Paper II) and the Hubble expansion (Paper IV) by invoking a macroscopic scalar field condensate. However, any modification to gravity must also satisfy the stringent constraints of Solar System tests, where General Relativity (GR) has been verified to high precision. In this paper, we demonstrate that the Harmodynamic scalar field naturally incorporates a screening mechanism analogous to the Chameleon effect. We show that in regions of high matter density or deep gravitational potential (such as the Solar System), the effective mass of the scalar field increases, causing the field interaction range to drop exponentially. This effectively decouples the scalar force from baryonic matter on planetary scales (the “Thin Shell” regime). We calculate the Post-Newtonian parameters (γP P N ) for the Harmodynamic model and confirm that deviations from General Relativity are suppressed by a factor of ∼ 10−15, well within the bounds set by the Cassini mission (|γ − 1| < 2.3 × 10−5 ). This validates the theory across all astrophysical scales.