Abstract: A solar concentrator comprises a pair of concentric reflectors having a spindle toroid geometry for focusing the collected solar radiation into a ring-shaped focal area, as opposed to the “point” or “line” focus of prior art configurations. In a preferred embodiment, each reflector is formed of a plurality of curved petals that are disposed in a contiguous, keystone arrangement that requires no additional fixturing to hold the petals in place. Such an arrangement reduces the weight, complexity and cost of the final solar concentrator structure.