A new design of a bright cascaded arc light source: measurements and simulations

Abstract

Profiling the arc channel of a cascaded arc into an hourglass-like shape results in an extremely high light output intensity (3.5 × 1012 Wm−2 m−1 sr−1 in the near-infrared) at an input power of 2.2 kW, a good stability (better than 5 × 10−4) and a small solid angle of the emitted light beam (Ω = 0.015 sr). These optical properties are advantageous for spectroscopic applications that require a high light intensity over a broad wavelength range in a small solid angle. The absolute light output is measured and is compared with a fast and flexible modelling scheme. These simulations are used to verify the arc performance and to guide arc design. The calculated emitted radiance at moderate arc input power agrees with the experiments within 30% for moderate input power.

H2: The Critical Juncture between Polymerization and Dissociation of Hydrocarbons in a Low‐temperature Plasma

“…The arc, which generates an expanding thermal plasma, consists of a stack of four water‐cooled copper plates with a central bore of 4 mm in diameter and has a total length of 24 mm (Figure 1). 5, 6 The electrically floating plates are insulated from each other by PVC spacers 35. The head of the arc contains three tungsten cathodes and the gas injection port.…”

Application of a dual-thermopile radical probe to expanding hydrogen plasmas

“…ε HFS is the surface IR emissivity and σ is the Stefan-Boltzmann constant. q other refers to heat disturbances other than conduction, convection, and thermal radiation, such as heat loads induced by light [24], ion fluxes [14], or molecular fluxes [23] from the plasma source.…”

“…In this ideal situation, we can extract the radical recombination heat loads using equation (4). It has been reported that the heat loads from the plasma source are radially symmetric with respect to the center of the nozzle, and they do not have homogeneous spatial distributions over the size of the DHFS [14,23,24]. Therefore, to reach the ideal situation, we aligned the DHFS to the center of the plasma source, as shown in figure 5.…”

“…However, this method might give large errors due to large background heat loads compared with the recombination heat load [22]. This problem may become very serious for a cascaded arc source, which is known to produce a range of heat loads, such as through gas and light, in addition to the plasma one [23,24]. To solve this problem, dual-sensor catalytic probes have been recently designed and demonstrated for high hydrogen radical fluxes [22,25].…”

Modelling of a pinched cascaded arc light source using argon

“…Burm et al proposed an arc with a varying channel diameter to locally enhance the electron density to enhance the radical yield of a flowing arc [13][14][15][16]. In the present work, we will make a numerical analysis of the behaviour of a stationary arc, in which a constricted channel is used to enhance the local electron density and light emission, as proposed in [17,18]. In order to increase the accuracy of the modelling, accurate and recent cross sections for the various elastic and inelastic processes are used.…”