A laboratory simulation instrument for metastable helium lidar

Area of Science:

• Atmospheric Science
• Plasma Physics
• Spectroscopy

Background:

• Metastable helium lidar offers potential for upper atmospheric detection.
• Implementation faces scientific challenges requiring laboratory validation.

Purpose of the Study:

• Develop a laboratory simulation instrument for metastable helium lidar.
• Investigate challenges in metastable helium lidar implementation.
• Provide data for helium lidar system design and calibration.

Main Methods:

• Constructed a simulation instrument with a metastable helium source, transmitter/receiver, and timing sequence.
• Generated metastable helium using a pulsed supersonic plasma jet.
• Employed backward fluorescence spectroscopy and direct absorption spectroscopy.

Main Results:

• Achieved metastable helium atom density of ~10^10 cm^-3.
• Demonstrated control over atom density, velocity distribution, and flow speed.
• Enabled investigation of saturation effects in absorption spectra.

Conclusions:

• The developed instrument is crucial for validating and refining metastable helium lidar.
• Provides essential laboratory data for helium lidar design and data analysis.
• Serves as a calibration tool for ground-based and spaceborne helium lidar.