Radial profiles of the X-ray flux F_X(r) (erg s⁻¹ cm⁻²) (top panels) and the secondary X-ray ionization rate ξ_X(r) (s⁻¹) (bottom panels) in NGC 1333-IRAS 2A (left) and NGC 1333-IRAS 4A (right) envelope models. In the bottom panels, the horizontal gray solid lines show the assumed constant cosmic-ray ionization rate ξ_CR (r) = 1.0 × 10⁻¹⁷ s⁻¹. In all panels the different line styles and colors in the radial F_X(r) and ξ_X (r) profiles denote models with different central star X-ray luminosities L_X.