Basis set expansion for inverse problems in plasma diagnostic analysis.

Area of Science:

• Plasma Physics
• Nuclear Fusion Diagnostics
• Computational Physics

Background:

• Instrumental measurements often transform physical data, necessitating inverse problem solutions.
• Diagnosing fast z pinches requires accurate recovery of plasma radiation source information.
• Previous methods faced challenges with data noise and source function discontinuities.

Purpose of the Study:

• To apply a basis set expansion method for recovering physical information from transformed plasma radiation data.
• To demonstrate the method's utility in analyzing fast z pinch experiments.
• To incorporate error propagation for uncertainty quantification in the inverted solutions.

Main Methods:

• Utilized a basis set expansion technique to solve inverse problems.
• Applied Abel inversion to time-gated x-ray images of wire array implosions.
• Developed an unfolding approach for neutron time-of-flight measurements from deuterium gas puff z pinches.

Main Results:

• Successfully recovered physical information about plasma radiation sources.
• Demonstrated the method's capability to handle noisy data, discontinuities, and artifacts.
• Implemented a propagation of errors calculation for estimating uncertainties.

Conclusions:

• The basis set expansion method offers a general and robust approach for inverse problems in plasma diagnostics.
• The method is effective for analyzing complex data from fast z pinch experiments.
• Accurate uncertainty quantification is crucial for interpreting inverted plasma source characteristics.