Near-Sun observations of an F-corona decrease and K-corona fine structure

Area of Science:

• Solar Physics
• Plasma Physics
• Space Science

Background:

• Remote observations of the solar corona (K-corona and F-corona) have been limited by distance.
• Previous studies have not confirmed a theoretically predicted dust-free zone near the Sun.
• The structure and initiation of small solar events remain uncertain.

Purpose of the Study:

• To image the solar corona at unprecedentedly close distances (0.16-0.25 AU) using the Parker Solar Probe.
• To investigate the existence of a dust-free zone near the Sun.
• To resolve the fine-scale plasma structure of small solar eruptions.

Main Methods:

• Imaging the solar corona during the Parker Solar Probe's perihelion passes.
• Analyzing F-coronal intensity at short elongations to infer dust distribution.
• Resolving fine-scale plasma structures of solar eruptions.

Main Results:

• Observed a decrease in F-coronal intensity at short elongations, suggesting a dust-free zone.
• Resolved fine-scale plasma structures of small solar eruptions, identifying magnetic flux ropes and magnetic islands.
• Confirmed large-scale coronal topology and revealed substreamers within coronal streamers.

Conclusions:

• The Parker Solar Probe observations provide evidence for a dust-free zone near the Sun.
• The study resolves previously unobserved magnetic structures in small solar eruptions.
• Coronal streamers are composed of smaller substreamers with continuous density fluctuations.