Time-resolved and multiple-angle Thomson scattering on gas-puff Z-Pinch plasmas at pinch time.

Area of Science:

• Plasma physics
• Z-pinch dynamics
• Laser diagnostics

Background:

• Gas-puff z-pinch implosions are crucial for fusion energy research.
• Accurate plasma condition measurements are vital for understanding implosion dynamics.
• Thomson scattering is a powerful diagnostic for probing plasma parameters.

Purpose of the Study:

• To implement and validate a time-resolved Thomson scattering diagnostic for neon gas-puff z-pinch plasmas.
• To measure electron temperature and density evolution during the implosion.
• To assess the diagnostic's sensitivity and limitations for electron density determination.

Main Methods:

• Utilized a 526.5 nm Thomson scattering laser system.
• Split the laser into two pulses for 7 ns total observation time with sub-nanosecond spectral resolution.
• Collected scattered light at 90° and 30° using a streak camera for temporal, spectral, and angular resolution.

Main Results:

• Measured electron densities ranging from 2 × 10^19 cm^-3 to 1.5 × 10^20 cm^-3.
• Observed electron temperatures increasing from 300 eV to 500 eV at pinch time, then decreasing.
• Determined that the current diagnostic setup provides constraints rather than precise measurements for electron density.

Conclusions:

• The Thomson scattering diagnostic successfully provided time-resolved measurements of electron temperature and density in neon gas-puff z-pinch implosions.
• The diagnostic's sensitivity to electron density is limited under the current experimental parameters.
• Calculations identified plasma regimes where this technique could offer more precise electron density measurements.