Thermal instabilities as an explanation of jet-like structures observed on laser irradiated thin planar targets at 1·06 μm and 0·35 μm wavelengths

Abstract

Filamentary and jet-like structures are observed in the interaction of a laser beam with aluminum and gold targets. The range of irradiance is 1013 to 5 × 1014 W cm−2 with nanosecond pulses. According to theoretical predictions these structures can be attributed to thermal instabilities. We show that the electrothermal instability grows more probably at the 0.35 μm laser wavelength whilst the magnetothermal instability develops at 1·06 μm. The jet-like structures occurring on the rear side of thin targets are discussed.