Alpha Heating and Burning Plasmas in Inertial Confinement Fusion.

Area of Science:

• Plasma Physics
• Nuclear Fusion Engineering

Background:

• Achieving thermonuclear ignition is a key goal in fusion energy research.
• A burning plasma regime, where alpha heating surpasses external energy input, is crucial for ignition.

Purpose of the Study:

• To establish a general method for estimating alpha heating levels.
• To determine the conditions for the onset of the burning plasma regime.
• To connect these conditions to measurable experimental parameters and fusion yield.

Main Methods:

• Development of a simplified implosion model.
• Derivation of a general relation connecting burning plasma onset to yield enhancement and measurable parameters.
• Establishment of a target-independent alpha-heating curve.

Main Results:

• A general relationship was derived to assess the burning plasma regime.
• An alpha-heating curve, independent of target specifics, was established for evaluating laser fusion experiments.
• The onset of the burning plasma regime in current National Ignition Facility (NIF) implosions requires a fusion yield of approximately 50 kJ.

Conclusions:

• The derived relation provides a universal tool for assessing fusion performance.
• The findings are applicable to all laser fusion experiments, including direct and indirect drive.
• A specific fusion yield threshold has been identified for achieving a burning plasma at NIF.