The proton-proton chain and stellar energy generation

What critical radius does a one-group diffusion model give for a bare sphere, and how far do a reflector and a change in enrichment move it? Useful evidence includes a discretised Laplacian, its lowest eigenvalue checked against the analytic (π/R)², critical radius and mass with the cross-sections cited, reflector savings taken from a separate two-region solve, and grid convergence reported as numerical error rather than physics.

This GioPhysics course map is an adaptable learning sequence, not academic credit, accreditation, or a universal university syllabus. It is written for a four-credit course of roughly three lecture hours plus two to three laboratory or computational hours a week across fifteen weeks, and it is deliberately more mathematical than University Physics I–IV: linear algebra and differential equations are working tools here, not background. Twenty units are mapped against a suggested fifteen-week delivery, so several units share a teaching week. Departments differ widely in how much formalism they expect at this stage; follow your institution's published scope, notation, laboratory programme, and assessment rules. A result should be checked against units, signs, limiting cases, and the conditions under which its model was derived.