NOVELTY - A gasifier (100), comprises: a reaction vessel (102) configured to gasify a hydrocarbon-containing feed material (106) to synthesis gas, where the reaction vessel includes inlet (108), outlet (112), and reaction region (123); an electrode positioned to be in electrical communication with reaction region; and a voltage source operatively coupled to the electrode. The voltage source and the electrode are cooperatively configured to generate a time varying electric field in the reaction region to effect electrodynamic mixing of charged chemical species in it during gasification.    USE - As gasifier for gasifying a hydrocarbon-containing feed material to generate synthesis gas comprising carbon monoxide, methane, and hydrogen; where the hydrocarbon-containing feed material includes wood, coal, municipal solid waste, recycled tires, or refuse derived fuel (all claimed).    ADVANTAGE - The agitation of the chemical species in the reaction region causes an increase in gasification reaction rate in the reaction region; a reduction in temperature of the gasification reaction in the reaction region; an efficiency increase in the gasification reaction; and/or a change in gasification reaction product generated during the act of gasifying.    DETAILED DESCRIPTION - A gasifier (100), comprises: a reaction vessel (102) configured to gasify at least one hydrocarbon-containing feed material (106) to synthesis gas; at least one electrode positioned to be in electrical communication with reaction region (123) of the reaction vessel; and a voltage source operatively coupled to the electrode. The voltage source and the electrode are cooperatively configured to generate a time varying electric field in the reaction region to effect electrodynamic mixing of charged chemical species in it during gasification. The reaction vessel includes at least one inlet (108) configured to receive a gasification medium that reacts with the feed material, an outlet (112) configured to allow the synthesis gas to exit from the reaction vessel, and a reaction region. The gasification medium includes air, steam, and oxygen. An INDEPENDENT CLAIM is included for a method of agitating charged chemical species in a reaction region of a reaction vessel of the gasifier during gasifying at least one hydrocarbon-containing feed material, involving: introducing the feed material into the reaction vessel; gasifying at least a portion of the feed material to generate synthesis gas; and during gasifying, applying a time varying voltage to at least one electrode to generate a time varying electric field in the reaction region that agitates at least some of the charged chemical species.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic diagram of an up draft gasifier.    Up draft gasifier (100)    Reaction vessel (102)    Fuel hopper (104)    Hydrocarbon-containing feed material (106)    Reaction region (123)