Transient spark discharge in air
Janda M., Machala Z., Pai D., Stancu G.D., Lacoste D., Laux C.O.
HAKONE XI, Oleron Island, France, September 7-12, p. 85-89 (2008)
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Abstract: We have investigated a novel type of streamer-to-spark transition
discharge in air at atmospheric pressure, named the transient spark (TS).
Although the applied voltage is DC, TS has a pulsed character with
very short (~100 ns) high current (~1 A) pulses, with repetitive
frequencies of some kHz. Thanks to the very short spark pulse duration,
given by the small internal capacitance of the discharge system and the
limiting series resistor, the plasma cannot reach LTE conditions.
The electrical and optical properties of TS were studied as functions
of the frequency and the gas composition by electric measurements,
ICCD camera imaging, photomultiplier tube recordings (PMT), and optical
emission spectroscopy with high temporal and spectral resolution.
The emission of N2 2nd and 1st positive, N2+ 1st negative, as well as that
of the atomic N and O lines, was detected. The non-equilibrium character
of TS was confirmed by comparisons with calculated vibrational
(3000-4000 K) and rotational (500-1500 K) temperatures. Additionally,
temporal emission profiles were obtained using the PMT measurements.
Transient spark provides a potential and was examined for various
applications, such as bio-decontamination or flue-gas cleaning (in air),
or CO2 decomposition followed by the synthesis of organic species
(in N2/CO2/H2O mixtures). These obtained results may help us gain a better
understanding of the plasma chemistry induced by TS leading to
the decomposition of organic species (bio-decontamination and
VOC abatement in air), as well as of the synthesis of organic species
from inorganic N2/CO2/H2O mixtures.
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