Generalized measurable ignition criterion for inertial confinement fusion

Area of Science:

• Physics
• Nuclear Fusion
• Plasma Physics

Background:

• Inertial confinement fusion (ICF) requires precise control over capsule implosions for successful ignition.
• Implosion nonuniformities significantly impact fusion performance and are challenging to quantify.
• Assessing ignition feasibility requires multidimensional criteria that incorporate real-world experimental conditions.

Purpose of the Study:

• To derive a multidimensional, measurable criterion for central ignition of ICF capsules.
• To incorporate the effects of implosion nonuniformities into ignition assessment.
• To provide a practical tool for evaluating cryogenic implosions at major facilities.

Main Methods:

• Derivation of a new ignition criterion based on measurable plasma parameters.
• Inclusion of neutron-averaged total areal density (rhoR(n)(tot)), ion temperature (T(n)), and yield over clean (YOC) as key parameters.
• Approximation of the criterion as chi=(rhoR(n)(tot))(0.8) x (T(n)/4.7)(1.7)YOC(mu)>1.

Main Results:

• A new criterion, chi, was developed to assess central ignition.
• The criterion quantifies implosion uniformity using the YOC parameter.
• Cryogenic implosions on OMEGA achieved chi values ranging from 0.02 to 0.03.

Conclusions:

• The derived criterion offers a robust method for evaluating ICF capsule performance.
• The criterion effectively accounts for critical factors like implosion nonuniformities.
• The results demonstrate the applicability of the criterion to current ICF experiments on OMEGA and NIF.