Two-dimensional spectral line emission reconstruction as a plasma diagnostic

Area of Science:

• Plasma Physics
• Optical Diagnostics
• Tomographic Reconstruction

Background:

• Traditional plasma diagnostics often rely on symmetry assumptions (e.g., Abel inversion).
• High-temperature plasmas can be obscured by surrounding cooler, emissive plasma layers.
• Accurate spatial and temporal measurements are vital for fusion energy research.

Purpose of the Study:

• To present a novel technique for reconstructing point-by-point light emission from plasma.
• To overcome limitations of existing methods by not assuming plasma symmetry.
• To enable detailed diagnostics of complex plasma structures.

Main Methods:

• Adaptation of tomographic X-ray scan principles for optical emission.
• Utilizing a 16-channel polychromator for light collection (0.4-A resolution, 1-microsecond response time).
• Reconstructing plasma light emission using multiple line-of-sight measurements from various angles.

Main Results:

• Achieved spatial resolution of 2 cm in a 14 x 24 cm vessel.
• Successfully reconstructed plasma light emission with spatial, temporal, and wavelength resolution.
• Utilized Stark and Doppler broadened spectral lines (H-beta, He II 4686-A) for density and temperature monitoring.

Conclusions:

• The developed technique provides detailed plasma diagnostics without symmetry assumptions.
• It is particularly effective for optically thick or complex plasma geometries.
• Enables advanced monitoring of local plasma density and temperature in fusion devices.