Development of an Interpretive Simulation Tool for the Proton Radiography Technique

TL;DR

This paper introduces a new simulation tool for proton radiography that models complex electromagnetic fields and helps interpret high-resolution images of high energy density plasmas, supporting experimental and theoretical research.

Contribution

The paper presents a novel, flexible simulation tool that accurately captures physics effects and allows interactive modification of electromagnetic fields for proton radiography analysis.

Findings

Successfully simulated proton radiographs of Weibel instability

Enabled deconstruction of radiograph features to underlying fields

Supported understanding of HED plasma phenomena

Abstract

Proton radiography is a useful diagnostic of high energy density (HED) plasmas under active theoretical and experimental development. In this paper we describe a new simulation tool that interacts realistic laser-driven point-like proton sources with three dimensional electromagnetic fields of arbitrary strength and structure and synthesizes the associated high resolution proton radiograph. The present tool's numerical approach captures all relevant physics effects, including effects related to the formation of caustics. Electromagnetic fields can be imported from PIC or hydrodynamic codes in a streamlined fashion, and a library of electromagnetic field `primitives' is also provided. This latter capability allows users to add a primitive, modify the field strength, rotate a primitive, and so on, while quickly generating a high resolution radiograph at each step. In this way, our tool enables the user to deconstruct features in a radiograph and interpret them in connection to specific underlying electromagnetic field elements. We show an example application of the tool in connection to experimental observations of the Weibel instability in counterstreaming plasmas, using $\sim 10^8$ particles generated from a realistic laser-driven point-like proton source, imaging fields which cover volumes of $\sim10 $ mm$^3$. Insights derived from this application show that the tool can support understanding of HED plasmas.