Measurement of the electron density in Transient Spark discharge

Abstract

The paper presents a study of transient spark: a streamer-to-spark transition discharge in air at atmospheric pressure. The transient spark (TS) is applicable for flue gas cleaning or biodecontamination and has a potential in combustion, and flow control applications. Despite the DC applied voltage, TS has a pulsed character with short (~10-100 ns) high current (>1A) pulses, with repetitive frequencies 1-10 kHz. The electron density n e ~10 17 cm −3 at maximum is reached in TS using relatively low power delivered to the plasma (0.2-3W). The estimate of temporal evolution of n e was derived from the resistance of plasma, obtained by detailed analysis of the electric circuit representing TS and the plasma diameter measurements using a fast iCCD camera. This estimate was compared with n e calculated from the measured Stark broadening of H α line. Good agreement was obtained when plasma diameter was approximated using the full width at the half maximum of the radial emission intensity profile of the plasma channel after the Abel inversion.

Study of Transient Spark Discharge Properties Using Kinetic Modeling

“…reaches a high value (∼1-10 A) for a short time, and n e can exceed 10 17 cm −3 [10]. The gas temperature in the plasma channel shortly after the spark increases to at least 1500-3000 K [10].…”

“…The gas temperature in the plasma channel shortly after the spark increases to at least 1500-3000 K [10]. However, complete thermalization of plasma is not possible due to small amount of energy stored in C that is delivered to the gap during the spark phase.…”

“…Thus, there is a constant demand for new atmospheric pressure discharges generating cold nonthermal plasmas with high TS is a dc-driven self-pulsing discharge of streamer-to-spark transition type with a repetition frequency of 1-10 kHz. During the spark phase of TS, an electron density as high as 10 17 cm −3 can be achieved [10]. The generated plasma is thus strongly ionized for a short time.…”

“…Unlike classical spark, TS thus generates highly reactive nonequilibrium nonthermal plasmas that were already successfully tested for several biological and environmental applications [11]- [14]. Basic research on TS using several electrical and optical diagnostic methods was also performed [10], [15]- [18]. However, further research on TS based on both experimental and computational techniques is needed for a better understanding of chemical processes initiated by TS.…”

“…Moreover, this model is able to describe macroscopic parameters such as plasma conductivity and current density in the plasma channel. The validity of the model was tested by comparing calculated electron densities with experimental data [10], [15]. Fig.…”