A reactor for reforming a hydrocarbon, and associated processes and systems, are described herein. In one example, a reactor is provided that is configured to use non-equilibrium gliding arc discharge plasma. In another example, the reactor uses a vortex flow pattern. Two stages of reforming are described. In a first stage, the hydrocarbon absorbs heat from the wall of the reactor and combusts to form carbon dioxide, carbon monoxide, and water. In a second stage, a gliding arc discharge is use to form syngas, which is a mixture of hydrogen gas and carbon monoxide. The heat generated by the combustion of the first stage transfers to the wall of the reactor and heated products of the second stage mix with incoming hydrocarbon to provide for partial recuperation of the reaction energy.