Space-Time Localization of Inner Heliospheric Plasma Turbulence Using Multiple Spacecraft Radio Links

TL;DR

This paper introduces a novel radio science technique using multiple spacecraft radio links to localize plasma turbulence in the inner heliosphere with high precision, aiding space weather prediction.

Contribution

The study demonstrates a new method for space-time localization of plasma irregularities using spacecraft radio signals, with proof-of-concept based on Cassini data from 2001-2002.

Findings

Achieved localization of plasma scattering regions within a few thousandths of an AU.

Determined the thickness of scattering regions to less than 0.02 AU.

Validated the method's potential for space weather applications.

Abstract

Radio remote sensing of the heliosphere using spacecraft radio signals has been used to study the near-sun plasma in and out of the ecliptic, close to the sun, and on spatial and temporal scales not accessible with other techniques. Studies of space-time variations in the inner solar wind are particularly timely because of the desire to understand and predict space weather, which can disturb satellites and systems at 1AU and affect human space exploration. Here we demonstrate proof-of-concept of a new radio science application for spacecraft radio science links. The differing transfer functions of plasma irregularities to spacecraft radio up- and downlinks can be exploited to localize plasma scattering along the line of sight. We demonstrate the utility of this idea using Cassini radio data taken in 2001-2002. Under favorable circumstances we demonstrate how this technique, unlike other remote sensing methods, can determine center-of-scattering position to within a few thousandths of an AU and thickness of scattering region to less than about 0.02 AU. This method, applied to large data sets and used in conjunction with other solar remote sensing data such as white light data, has space weather application in studies of inhomogeneity and nonstationarity in the near-sun solar wind.