Observing the evolution of the Sun's global coronal magnetic field over eight months

The magnetic field in the Sun's corona stores energy that can be released to heat the coronal plasma and drive solar eruptions. Measurements of the global coronal magnetic field have been limited to a few snapshots. We present observations using the Upgraded Coronal Multi-channel Polarimeter, which provided 114 magnetograms of the global corona above the solar limb spanning approximately eight months. We determined the magnetic field distributions at different solar radii in the corona, and monitored the evolution at different latitudes over multiple solar rotations. We found varying field strengths from <1 to 20 Gauss within 1.05-1.6 solar radii and a signature of active longitude in the coronal magnetic field. Coronal models are generally consistent with the observational data, with larger discrepancies in high-latitude regions.

Zihao Yang, Hui Tian, Steven Tomczyk, Xianyu Liu, Sarah Gibson, Richard J. Morton, Cooper Downs