Coulombic Criticality in General Dimensions

Debye-H\"uckel theory for spheres of diameter a with charges ^±q is extended to general dimension d. Explicit results include Bjerrum association of +/- ions and the dipole-ionic solvation energy. For all $d>2$ a critical point terminates conducting-liquid-conducting-vapor coexistence: The critical density ρc*=ρcaᵈ falls with d2, but Tc*≡kBTca^d-2q² rises. When $d=2$, an insulating vapor appears for T*≤1/4 (the Kosterlitz-Thouless point), separated from conducting fluid by an infinite-order critical line ending at a tricritical point: ρₜ*=ρc*(d→2)0.004, Tₜ*=Tc*(d→2)1/4forρ*>ρₜ* the transition is first order.