Measurement of plasma-surface energy fluxes in an argon rf-discharge by means of calorimetric probes and fluorescent microparticles

On the heating of nano- and microparticles in process plasmas

“…The experimental setup (PULVA-INP) as well as the procedure for the measurement of the particle temperature by temperature-dependent fluorescence have been extensively described elsewhere [33,34]. The plasma parameters n e and V e ,, measured by a Langmuir probe, show pronounced differences under admixture of molecular gas as depicted in figs.…”

“…The electronic and energetic conditions at the surface of small particles in low pressure plasmas are affected by their size and geometry [36][37][38][39]. Quickly a balance is archieved [23,33,34], resulting in the establishment of an equilibrium temperature T µ .…”

“…Commonly, particles and surfaces in plasmas tend to be negatively charged [23][24][25][26][27][28][29][30][31][32][33][34][35] due to the much larger mobility of plasma electrons compared to that of positive ions. As the temperature of electrons in non-thermal plasmas is significantly higher than that of heavy species, the collection of electrons is even more pronounced in cold plasmas.…”

“…Oliver and Enikov measured the incandescent radiation from particles in a plasma jet, which of course is only possible at rather high particle temperatures above 1000 K [46]. A rather novel method for the measurement of particle temperatures utilizes temperature-sensitive spectral features of phosphor grains, which are excited by means of an external illumination source [33,44].…”

“…Several studies addressed the grain temperature, both theoretically [39][40][41][42] and experimentally [33,34,[43][44][45][46][47]. For example, Daugherty and Graves measured the temperature-dependent decay time of the fluorescence of manganese activated magnesium fluorogermanate particles in a pulsed argon discharge during the plasma-off phase [43].…”