On the fundamental relation of laser schlieren deflectometry for temperature measurements in filamentary plasmas
Authors | |
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Year of publication | 2015 |
Type | Article in Periodical |
Magazine / Source | EUROPEAN PHYSICAL JOURNAL-APPLIED PHYSICS |
MU Faculty or unit | |
Citation | |
Web | http://www.epjap.org/articles/epjap/abs/2015/08/ap140491/ap140491.html |
Doi | http://dx.doi.org/10.1051/epjap/2015140491 |
Field | Plasma physics |
Keywords | DISCHARGE; AIR |
Description | Recently, laser schlieren deflectometry (LSD) had been successfully employed as a temperature measurement method to reveal the heat convection generated by micro filaments of a self-organized non-thermal atmospheric plasma jet. Based on the theory of the temperature measurements using LSD, in this work, three approaches for an application of the method are introduced: (i) a hyperbolic-like model of refractive index is applied which allows an analytical theory for the evaluation of the deflection angle to be developed, (ii) a Gaussian shape model for the filament temperature is implemented which is analyzed numerically and (iii) an experimental calibration of the laser deflection with a gas mixture of helium and argon is performed. Thus, these approaches demonstrate that a universal relation between the relative maximum temperature of the filament core (T1/T0) and a the maximum deflection angle d_1 of the laser beam can be written as T1/T0=(1-d_1/d_0)^{-1}, where d_0 is a parameter that is defined by the configuration of the experiment and by the assumed model for the shape of the temperature profile. |
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