Measured Temperatures of Strong Shock Waves in Argon

Abstract

Plane shocks generated in atmospheric pressure argon by detonating Comp B-3 have been viewed with a photomultiplier-interference filter system. Visible radiation from these Mach 27 shocks was that from a blackbody at a color temperature of 29 000°±1000°K, about 20% higher than calculated. The risetime to peak intensity is interpreted in terms of increasing opacity, and consequently of emissivity, as the shocked zone increases in thickness. Photon absorption coefficients based on this interpretation are in reasonable accord with those calculated from a modified Kramers's formula.

Contributed Review: Absolute spectral radiance calibration of fiber-optic shock-temperature pyrometers using a coiled-coil irradiance standard lamp

“…Such factors are necessary to convert recorded radiance histories into equilibrium thermodynamic temperature of the material in the shockcompressed state. This is true whether the ultimate method of determining temperature is from absolute intensity 6,7,20,21 or from fitting the shape of the observed spectrum. 22,23 The accuracy and precision of pyrometry measurements never exceeds the quality of the calibration light source.…”

“…Typical inert samples shock-compressed into the megabar pressure range exhibit, depending on the material compressibility, temperatures of 3000-30 000 K 1,5,6,10,20 and emissivities in excess of 0.9 in the visible spectral range. 1,[24][25][26] Ideally, accurate calibration of fast time-response optical pyrometers would use isothermal blackbodies at the temperature range of interest.…”

“…The vast majority of these measurements employed currently discontinued tungsten ribbon standards of spectral radiance. 3,11,14,20,27,28 Less frequently, since 1983, 32,33 coiled tungsten halogen standards of spectral irradiance 5,9,10,29-31 have been used. There are only a few known exceptions to tungsten lamps for calibrating shock pyrometers.…”

Ultraviolet Emissions from Explosive Detonation Breakout

“…While common detonation wave and fireball temperatures are in the vicinity of 3000 K, the temperatures initially created behind the air shock can exceed 10 000 K. 1 This effect has been studied in some previous works, 1,2 and the high temperatures form the basis for the widely used argon candle illumination source. [3][4][5] Despite the high brightness of these events and the potential to influence post-detonation fireball conditions, few studies have researched this phenomenon in detail. Our previous paper looked at PBX-9407 in air with detailed measurements in the visible spectral region, and a low resolution survey of the ultraviolet.…”