(a) Ambient gas resistivities as functions of temperature and (b) the CPD resistivities as functions of cylindrical radius. The ambient gas resistivities are calculated for ρ = 1.6 × 10⁻¹² g cm⁻³ (blue line), 5.0 × 10⁻¹² g cm⁻³ (orange line), and 15 × 10⁻¹² g cm⁻³ (green line). For the calculation of the CPD resistivities, we take ﹩{T}_{{\rm{\max }}}=1500\,{\rm{K}}﹩ (blue solid line) and 2000 K (orange dashed line). See the fourth paragraph in Section 2.5 for details.