This paper presents quantitative planar laserinduced fluorescence (PLIF) imaging of nitric oxide (NO) in a transient-arc direct-current plasmatron igniter using premixed air/fuel mixtures. Quantitative measurements of NO are reported as a function of gas flow rate (2050 standard cubic feet per hour), plasma power (100900 mA, 150750 W), and equivalence ratio (0.71.3). Images were corrected for temperature effects by using 2-D temperature field measurements obtained with infrared thermometry and calibrated by a more accurate multiline fitting technique. The signals were then quantified using an NO addition method and spectroscopic laser-induced fluorescence mode領(lǐng) of NO. NO PLIF images and single-point NO concentrations are presented for both plasma-discharge-only and methane/air plasma-enhanced combustion cases. NO formation occurs predominantly through N2(v) + O NO + N for the plasmadischarge- only case without combustion. The NO concentration for the plasma-enhanced combustion case (5003500 ppm) was an order of magnitude less than the plasma-discharge-only case (800015 000 ppm) due to the reduction of plasma reactions by the methane. Experiments show the linear decay of NO from equivalence ratio 0.81.2 under the same flow condition and discharge current. Index TermsNitric oxide (NO), plasma torch, plasma-assisted combustion. PLIF平面激光誘導(dǎo)熒光火焰燃燒檢測系統(tǒng)