Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Washington Headquarters Services, Directorate SUPPLEMENTARY NOTESNo copyright is asserted in the United States under Title 17, U.S. code. The U.S. Government has a royalty-free license to exercise all rights under the copyright claimed herein for Government purposes. All other rights are reserved by the copyright owner. 12a. DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release: distribution is unlimited. 12b. DISTRIBUTION CODEA ABSTRACT (Maximum 200 Words)Plasma reactors can be operated as a paniculate trap or as a NO x converter. Particulate trapping in a plasma reactor can be accomplished by electrostatic precipitation. The soluble organic fraction of the trapped particulates can be utilized for the hydrocarbonenhanced oxidation of NO to N0 2 . The NO z can then be used to non-thermally oxidize the carbon fraction of the particulates. The oxidation of the carbon fraction by N0 2 can lead to reduction of NO x or backconversion of N0 2 to NO. This paper examines the hydrocarbon and electrical energy density requirements in a plasma for maximum NOx conversion in both heavy-duty and light-duty diesel engine exhaust. The energy density required for complete oxidation of hydrocarbons is also examined and shown to be much greater than that required for maximum NO x conversion. The reaction of N0 2 with carbon is shown to lead mainly to backconversion of N0 2 to NO. These results suggest that the combination of the plasma with a catalyst will be required to reduce the NO x and oxidize the hydrocarbons. The plasma reactor can be operated occasionally in the arc mode to thermally oxidize the carbon fraction of the particulates. SUBJECT TERMS ABSTRACTPlasma reactors can be operated as a paniculate trap or as a NO x converter. Particulate trapping in a plasma reactor can be accomplished by electrostatic precipitation. The soluble organic fraction of the trapped particulates can be utilized for the hydrocarbonenhanced oxidation of NO to N0 2 . The N0 2 can then be used to non-thermally oxidize the carbon fraction of the particulates. The oxidation of the carbon fraction by N0 2 can lead to reduction of NO x or backconversion of N0 2 to NO. This paper examines the hydrocarbon and electrical energy density requirements in a plasma for maximum NO x conversion in both heavy-duty and light-duty diesel engine exhaust. The energy density required for complete oxidation of hydrocarbons is also examined and shown to be much greater than that required for maximum NO x conversion. The reaction of N0 2 with carbon is shown to lead mainly to backconversion of N0 2 to NO. These results suggest...