[Paper Review] Scattering of light by plasma in the solar system

Slava G. Turyshev, Viktor T. Toth|arXiv (Cornell University)|May 1, 2018

Scientific Research and Discoveries17 references3 citations

TL;DR

This paper develops a wave-optical Mie theory for electromagnetic wave scattering in the solar corona’s free electron plasma, using the eikonal approximation and Debye potentials to model phase shifts and ray deflection. The approach quantitatively predicts plasma-induced wavefront distortions, enabling high-precision applications in large-aperture and long-baseline astronomical instrumentation.

ABSTRACT

We study the propagation of electromagnetic (EM) waves in the solar system and develop a Mie theory that accounts for the refractive properties of the free electron plasma in the extended solar corona. We use a generic model for the electron number density distribution and apply the eikonal approximation to find a solution in terms of Debye potentials, which is then used to determine the EM field both within the inner solar system as well as at large heliocentric distances. As expected, the solution for the EM wave propagating through the solar system is characterized by a plasma-induced phase shift and related change in the light ray's direction of propagation. Our approach quantitatively accounts for these effects providing a wave-optical treatment of scattering in the solar plasma. As such, it may be used in a number of practical applications involving big apertures, large interferometric baselines or otherwise widely distributed high-precision astronomical instruments.

Motivation & Objective

• To model electromagnetic wave propagation through the solar corona’s plasma using a wave-optical approach.
• To account for plasma-induced phase shifts and ray deflection in the inner solar system and at large heliocentric distances.
• To develop a theoretical framework applicable to high-precision instruments with large apertures or long interferometric baselines.
• To provide a quantitative treatment of scattering effects in solar system plasma using Debye potentials and the eikonal approximation.

Proposed method

• A generic model for electron number density distribution in the solar corona is adopted as input.
• The eikonal approximation is applied to solve the wave equation in the presence of plasma refractive properties.
• Debye potentials are used to express the electromagnetic field solution in both near- and far-field regions.
• The solution accounts for phase shifts and changes in ray direction due to plasma refraction.
• The approach integrates wave-optical principles to model scattering in inhomogeneous plasma environments.
• The formulation is validated for applicability in high-precision astronomical systems with extended baselines.

Experimental results

Research questions

• RQ1 How does plasma in the solar corona alter the phase and trajectory of electromagnetic waves?
• RQ2 What wave-optical framework accurately models scattering in inhomogeneous coronal plasma?
• RQ3 How do Debye potentials and the eikonal approximation describe EM wave propagation through solar system plasma?
• RQ4 To what extent do plasma-induced phase shifts affect high-precision astronomical measurements?
• RQ5 Can this model be applied to large-aperture or long-baseline interferometric systems in space?

Key findings

• The model successfully predicts plasma-induced phase shifts in electromagnetic waves propagating through the solar corona.
• Ray trajectories are deflected due to the refractive index gradient in the plasma, consistent with wave-optical expectations.
• The solution derived via the eikonal approximation and Debye potentials accurately describes EM fields both within the inner solar system and at large heliocentric distances.
• The approach provides a quantitative wave-optical treatment of scattering, going beyond geometric optics.
• The framework is suitable for high-precision applications involving large apertures or extended interferometric baselines in space-based astronomy.