Electric field in APTD in nitrogen determined by EFISH, FNS/SPS ratio, α-fitting and electrical equivalent circuit model

Abstract

We investigate the electric field development in weak microseconds-lasting atmospheric pressure Townsend discharge (APTD) operated in barrier discharge arrangement in pure nitrogen. The electric field is determined using four different methods: laser-aided EFISH (electric field induced second harmonics), optical emission- based FNS/SPS (first negative/second positive systems of molecular nitrogen) intensity ratio, electrical equivalent circuit approach and via determination of the Townsend first coefficient α(E/N) from the optical emission profile. The resulting values of the electric field obtained by the respective methods, regardless of the differences in absolute values, lie within a reasonable range. Limitations and advantages of all methods are discussed in detail for investigated discharge. The EFISH measurements are supported by re- computation of the effective interaction-path of the laser using an electrostatic model. The FNS/SPS method provides systematically higher values compared to other methods. We discuss in detail the potential origins of this discrepancy as this method is at the limit of its applicability due to the impossibility of fully verifying the underlying assumptions. The focused discussion addresses best-practice issues and identifies possible future steps to improve each of the four methods under given conditions.

Ionizing Waves in Surface Dielectric Barrier Discharges Plasma Actuators

“…m 2 [28], where a formula was reported connecting the intensity ratio to the strength. A recent paper discussing measurements of electric field strength can als quoted [29]. To put it in perspective, this is about five times the dielectric strength o at STP.…”

“…First of all, it could be inferred that such ratio values correspond either to electron temperatures of about 4-5 eV [27] or to a reduced effective electric field E/N of about 6 × 10 −19 V•m 2 [28], where a formula was reported connecting the intensity ratio to the field strength. A recent paper discussing measurements of electric field strength can also be quoted [29]. To put it in perspective, this is about five times the dielectric strength of air at STP.…”

Complex characterisation of Cr-doped α-Al 2O3 for DBD applications

“…Furthermore, the extended WD of the 5Cr sample in contrast with very narrow APTD WD for the 1Cr sample cannot be fully explained by the SPD only and remains a very interesting task for future research, where e.g. E/N in APTD [49] will be determined for various dielectric barriers or secondary emission coefficients will be included.…”

Characterization of a filamentary discharge ignited in a gliding arc plasmatron operated in nitrogen flow

“…A spatial resolution of several micrometers can be achieved by application of a calibrated intensified charge-coupled device (ICCD) camera and Abel inversion of the measured images [14]. Reliability of this diagnostics method was successfully verified at different plasma conditions by comparison with an electric probe [26,27], multipole resonance probe [28], capacitive probe [29] and laseraided electric field induced second harmonics [30].…”