Coronal Streamer Brightness Profiles Investigated with BriLo Using Parker Solar Probe White-Light Data

Area of Science:

• Solar Physics
• Plasma Physics
• Heliophysics

Background:

• Coronal streamers are key structures in the solar corona, influencing space weather.
• Previous methods for streamer localization often require multiple spacecraft or complex modeling.
• Understanding streamer properties is crucial for space weather prediction.

Purpose of the Study:

• To introduce and validate the novel Brightness-Location (BriLo) method for localizing extended coronal features.
• To assess the geometrical properties, including angular width, of coronal streamers.
• To compare BriLo results with existing triangulation techniques and heliospheric current sheet models.

Main Methods:

• Developed the BriLo method, a single-spacecraft technique utilizing Thomson scattering theory and white-light imaging.
• Validated BriLo through geometrical triangulation using data from STEREO A COR2 and SOHO C2-C3 coronagraphs.
• Applied BriLo to Parker Solar Probe (PSP) Wide-Field Imager for Solar Probe (WISPR) data from encounters 1-17, analyzing two data products (L3 and LX).

Main Results:

• BriLo successfully determines the longitude, latitude, and angular width of coronal streamers.
• Results from L3 and LX data show good agreement in streamer directionality (2-30° longitude, 1-6° latitude differences).
• BriLo-derived locations are consistent with triangulation, and helmet streamers are found near the heliospheric current sheet (HCS), while pseudostreamers are near active regions.

Conclusions:

• The BriLo method is a robust tool for streamer localization and geometrical property estimation using single-spacecraft data.
• LX data yield realistic streamer widths (several to ten degrees), whereas L3 data produce unrealistically narrow values due to F-corona removal and background estimation issues.
• BriLo aids in assessing and validating white-light imaging techniques for coronal feature analysis.