Diagnostic-based modeling on a micro-scale atmospheric-pressure plasma jet

2010 ◽  
Vol 82 (6) ◽  
pp. 1209-1222 ◽  
Author(s):  
Jochen Waskoenig ◽  
Kari Niemi ◽  
Nikolas Knake ◽  
Lucy Marie Graham ◽  
Stephan Reuter ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Atomic Oxygen ◽  
Atmospheric Pressure Plasma ◽  
Plasma Jet ◽  
Photon Absorption ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Dissociative Excitation ◽  
Atmospheric Pressure Plasma Jet ◽  
Pressure Plasma

Diagnostic-based modeling (DBM) actively combines complementary advantages of numerical plasma simulations and relatively simple optical emission spectroscopy (OES). DBM is applied to determine spatial absolute atomic oxygen ground-state density profiles in a micro atmospheric-pressure plasma jet operated in He–O2. A 1D fluid model with semi-kinetic treatment of the electrons yields detailed information on the electron dynamics and the corresponding spatio-temporal electron energy distribution function. Benchmarking this time- and space-resolved simulation with phase-resolved OES (PROES) allows subsequent derivation of effective excitation rates as the basis for DBM. The population dynamics of the upper O(3p3P) oxygen state (λ = 844 nm) is governed by direct electron impact excitation, dissociative excitation, radiation losses, and collisional induced quenching. Absolute values for atomic oxygen densities are obtained through tracer comparison with the upper Ar(2p1) state (λ = 750.4 nm). The resulting spatial profile for the absolute atomic oxygen density shows an excellent quantitative agreement to a density profile obtained by two-photon absorption laser-induced fluorescence spectroscopy.

Enhancement of hydrogen radical density in atmospheric pressure plasma jet by a burst of nanosecond pulses at 1 MHz

2021 ◽  
Author(s):  
Huang Bangdou ◽  
Cheng Zhang ◽  
Hao Sun ◽  
Dmitry A Sorokin ◽  
Victor F Tarasenko ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Atmospheric Pressure Plasma ◽  
Plasma Jet ◽  
Active Species ◽  
Thermal Plasmas ◽  
Photon Absorption ◽  
Atmospheric Pressure Plasma Jet ◽  
Axial Distribution ◽  
Atom Density ◽  
Pressure Plasma

Abstract The generation and enhancement of active species in non-thermal plasmas are always decisive issues referring to their successful applications. In this work, atmospheric pressure plasma jet (APPJ) is generated in Ar + 1% CH4 gas flow by a bipolar nanosecond high-voltage (HV) source with a maximum pulse repetition rate up to 1 MHz (i.e., minimum pulse interval ΔT = 1 µs) in burst mode. The absolute density of hydrogen atom at ground state is measured by the two-photon absorption laser induced fluorescence (TALIF) method. It is observed that with ΔT = 1 µs, the H atom density keeps increasing during the first eight HV pulses and later on the H atom density maintains at a quasi-stable value while more HV pulses are applied. When decreasing ΔT from 10 to 1 µs while keeping the total number of HV pulses the same (with similar coupled energy), the peak H atom density increases by a factor of more than four times, but the decay of H atom density after the pulse burst with ΔT = 1 µs is faster. Another effect of short ΔT is to extend the axial distribution of H atom outside the APPJ’s nozzle and the ΔT = 2 μs case has the highest averaged H atom density when taking its temporal evolution and axial distribution into consideration. This work proposes that the intensive nanosecond HV burst is an efficient approach to enhance the active species density in non-thermal plasmas when a rapid response is required.

Absolute atomic oxygen density profiles in the discharge core of a microscale atmospheric pressure plasma jet

2008 ◽  
Vol 93 (13) ◽  
pp. 131503 ◽  
Author(s):  
Nikolas Knake ◽  
Kari Niemi ◽  
Stephan Reuter ◽  
Volker Schulz-von der Gathen ◽  
Jörg Winter
Keyword(s):  
Atmospheric Pressure ◽  
Atomic Oxygen ◽  
Atmospheric Pressure Plasma ◽  
Plasma Jet ◽  
Atmospheric Pressure Plasma Jet ◽  
Density Profiles ◽  
Pressure Plasma
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