Real-time imaging of density ducts between the plasmasphere and ionosphere

TL;DR

This paper presents the first direct visual evidence of field-aligned density ducts connecting the Earth's ionosphere and plasmasphere, using a novel imaging technique to analyze their structure, height, and motion.

Contribution

It introduces a new ground-based imaging method that captures and characterizes the first direct wide-angle observations of these plasma ducts.

Findings

Detected regularly spaced, field-aligned density structures.

Established the heights and motions of the ducts.

Provided direct visual evidence of these plasma structures.

Abstract

Ionization of the Earth's atmosphere by sunlight forms a complex, multi-layered plasma environment within the Earth's magnetosphere, the innermost layers being the ionosphere and plasmasphere. The plasmasphere is believed to be embedded with cylindrical density structures (ducts) aligned along the Earth's magnetic field, but direct evidence for these remains scarce. Here we report the first direct wide-angle observation of an extensive array of field-aligned ducts bridging the upper ionosphere and inner plasmasphere, using a novel ground-based imaging technique. We establish their heights and motions by feature-tracking and parallax analysis. The structures are strikingly organized, appearing as regularly-spaced, alternating tubes of overdensities and underdensities strongly aligned with the Earth's magnetic field. These findings represent the first direct visual evidence for the existence of such structures.