Validating Forward Modeling and Inversions of Helioseismic Holography Measurements

TL;DR

This study evaluates the accuracy of forward models and inverse methods in helioseismic holography using synthetic data, demonstrating successful flow reconstructions in the Sun's upper layers but limitations at greater depths.

Contribution

It provides the first comprehensive test of inverse modeling for flows with lateral-vantage holography using sensitivity functions derived in the Born approximation.

Findings

Forward travel times match measurements well in the shallow layers.

Inversions accurately recover flows in the upper 3Mm of the Sun.

Deeper flow inversions are limited by noise.

Abstract

Here we use synthetic data to explore the performance of forward models and inverse methods for helioseismic holography. Specifically, this work presents the first comprehensive test of inverse modeling for flows using lateral-vantage (deep-focus) holography. We derive sensitivity functions in the Born approximation. We then use these sensitivity functions in a series of forward models and inversions of flows from a publicly available magnetohydrodynamic quiet-Sun simulation. The forward travel times computed using the kernels generally compare favorably with measurements obtained by applying holography, in a lateral-vantage configuration, on a 15-hour time series of artificial Dopplergrams extracted from the simulation. Inversions for the horizontal flow components are able to reproduce the flows in the upper 3Mm of the domain, but are compromised by noise at greater depths.