Three-dimensional flow velocity determination using laser-induced fluorescence method with asymmetric optical vortex...

Area of Science:

• Plasma Physics
• Spectroscopy
• Optical Physics

Background:

• Laser-induced fluorescence (LIF) is a standard diagnostic for plasma properties.
• Conventional LIF often uses plane waves, limiting its ability to probe complex flow dynamics.
• Measuring 3D plasma velocity vectors requires advanced spectroscopic techniques.

Purpose of the Study:

• To introduce and validate a new LIF method using asymmetric optical vortex beams (aOVLIF) for plasma flow velocity measurement.
• To investigate the feasibility of using aOVLIF for simultaneous temperature determination.
• To analyze the impact of beam propagation on measurement sensitivity.

Main Methods:

• Numerical calculation of LIF spectra using asymmetric optical vortex beams.
• Simulation of low-temperature plasma parameters to model spectral responses.
• Analysis of spectral frequency shifts caused by ion flow across the beam.

Main Results:

• Ion flow across the beam induces a measurable frequency shift in LIF spectra.
• The aOVLIF method demonstrates capability for plasma temperature measurements.
• Propagation effects of asymmetric optical vortex beams minimally affect transverse flow velocity sensitivity.

Conclusions:

• The asymmetric optical vortex beam laser-induced fluorescence (aOVLIF) method is a viable technique for plasma flow velocity measurement.
• aOVLIF leverages the phase structure of optical vortices for enhanced diagnostic capabilities.
• This method offers potential for determining 3D velocity vectors, improving upon conventional LIF.