Unsupervised Discovery of Inertial-Fusion Plasma Physics using Differentiable Kinetic Simulations and a Maximum Entropy Loss Function

Abstract

Plasma supports collective modes and particle-wave interactions that leads to complex behavior in inertial fusion energy applications. While plasma can sometimes be modeled as a charged fluid, a kinetic description is useful towards the study of nonlinear effects in the higher dimensional momentum-position phase-space that describes the full complexity of plasma dynamics. We create a differentiable solver for the plasma kinetics 3D partial-differential-equation and introduce a domain-specific objective function. Using this framework, we perform gradient-based optimization of neural networks that provide forcing function parameters to the differentiable solver given a set of initial conditions. We apply this to an inertial-fusion relevant configuration and find that the optimization process exploits a novel physical effect that has previously remained undiscovered.

2nd AI4Science Workshop at the 39th International Conference on Machine Learning (ICML), 2022

References in corpus (5)

• Evidence for Electron Landau Damping in Space Plasma Turbulence
• Coherent control of plasma dynamics
• Convective Raman Amplification of Light Pulses Causing Kinetic Inflation in Inertial Fusion Plasmas
• Adjoint approach to calculating shape gradients for three-dimensional magnetic confinement equilibria. Part II: Applications
• Gradient-based optimization of 3D MHD equilibria