This study combines theoretical and experimental approaches to systematically link plasma dynamics with reaction engineering. A novel reactor design with laminar gas flow and magnetically induced nonthermal plasma rotation enables precise determination of residence times and effective plasma volumes. Two complementary models‐from gas‐phase and discharge‐channel perspectives‐quantify gas–plasma interaction and derive effective energy input parameters such as the effective specific energy input. Introducing a normalized voltage allows reactor‐scale comparison, distinguishing smooth reattachment (≥30 V/mm dE ) from restrike regimes (<20 V/mm dE ). Experimentally, doubling the magnetic flux density increased the rotation frequency from 21 to 80 Hz and CO 2 conversion (2.4% → 4.8%) while reducing energy input from 1.2 to 0.3 eV/molecule each plasma pulse. Scaling the cathode diameter from 30 to 100 mm enabled plasma powers above 1.5 kW, with conversion limited by arc stability rather than power. Theoretical analysis indicated plasma coverage ratios up to 90% in optimized configurations. Further improvements through magnetic field tuning, operation near the glow‐to‐arc transition, and enhanced quenching could raise overall CO 2 conversion beyond 50%. By embedding reaction‐engineering metrics into plasma characterization, this work establishes a quantitative framework for optimizing rotating arcs towards energy‐efficient CO 2 splitting.
Kaufmann et al. (Sun,) studied this question.