Spatial and temporal evolution of argon sparks.

Area of Science:

• Plasma Physics
• Laser-Induced Breakdown Spectroscopy (LIBS)
• Atomic Spectroscopy

Background:

• Laser-produced plasmas are crucial for various applications.
• Understanding plasma properties like electron temperature and density is essential for controlling these applications.
• Argon sparks offer a well-defined plasma environment for fundamental studies.

Purpose of the Study:

• To investigate the temporal and spatial evolution of laser-created argon sparks.
• To measure electron temperature and density in the spark plasma.
• To analyze the influence of experimental parameters on plasma characteristics.

Main Methods:

• Utilized a frequency-doubled Nd:YAG laser (532 nm, 8 ns pulses) to generate argon sparks at atmospheric pressure.
• Employed gated photography (2 ns gate) for high-speed imaging of spark evolution.
• Performed optical emission spectroscopy to analyze spectral line broadening and intensities.

Main Results:

• Determined electron density using the Stark broadening of spectral emission lines.
• Calculated electron temperature via Boltzmann plot analysis of singly ionized argon lines.
• Observed dependencies of electron temperature and density on parameters like laser energy, distance from the focal point, and time delay.

Conclusions:

• Successfully characterized laser-created argon sparks using optical emission spectroscopy.
• Established methods for measuring key plasma parameters (electron temperature and density).
• Provided insights into the influence of experimental conditions on spark plasma properties, valuable for optimizing laser-plasma interactions.