In-flight particle characteristics are clarified experimentally for a DC-RF hybrid plasma flow for various operating pressures. A recirculation effect in a coil region becomes small for a DC-RF hybrid plasma flow, and particle velocity increases with decreasing operating pressure and the swirl gas ratio. Particles are heated effectively by increasing operating pressure and the swirl gas ratio. Multi-input and multi-objective optimization is conducted to obtain Pareto-optimal resolutions, in which particle velocity and particle temperature in the downstream region are maximized for high quality in-flight particle processing. (c) 2005 Published by Elsevier B.V.