Collective optical Thomson scattering in pulsed-power driven high energy density physics experiments (invited)

Area of Science:

• Plasma Physics
• High Energy Density Physics
• Laser-Plasma Interactions

Background:

• Magnetized high energy density physics experiments require precise plasma diagnostics.
• Optical collective Thomson scattering (TS) is a key technique for probing plasma properties.
• Previous methods had limitations in spatial and temporal resolution for complex plasma structures.

Purpose of the Study:

• To detail the implementation and capabilities of an optical collective Thomson scattering diagnostic system.
• To demonstrate its application in diagnosing magnetized high energy density physics experiments.
• To enable accurate measurements of plasma temperature and velocity in diverse plasma objects.

Main Methods:

• Utilized a 532 nm Nd:YAG laser (3 J, 8 ns) for Thomson scattering.
• Collected scattered light from 100 μm plasma volumes using optical fiber arrays.
• Employed an imaging spectrometer with a gated intensified CCD to analyze ion-acoustic waves.

Main Results:

• Successfully diagnosed various high-temperature plasma objects (10^17-10^19 cm^-3, 10 eV-keV).
• Enabled simultaneous measurements of bulk plasma flow velocity components using multiple collection systems.
• Provided direct measurements of temperature and velocity, including drift velocities in magnetic reconnection.

Conclusions:

• The optical collective Thomson scattering system is a versatile and effective diagnostic for high energy density physics.
• It provides crucial data on temperature and flow dynamics in magnetized plasmas.
• This diagnostic advances the understanding of phenomena like magnetized shocks, plasma jets, and magnetic reconnection.