Parker Solar Probe finds the Sun’s corona at peak activity still resembles a simple tilted dipole
arXiv: 2611.12416v1
During mid‑2025, when the Sun was near maximum of its magnetic cycle, the Parker Solar Probe flew close to the Sun on its 23rd and 24th perihelion passes. The spacecraft measured plasma and magnetic‑field data at about 10 solar radii. The data show that the large‑scale coronal field was organized as a single tilted dipole, rather than a messy, multipolar arrangement. Figure 1 displays the dipole axis orientation during these encounters and confirms that it remained steady between March and June 2025.
Figure 1. Solar activity across 2018–2026. Panel A shows sunspot numbers; panel B displays the magnetic‑field butterfly diagram with the dipole axis overlay; panel C counts CMEs; panel D presents dipole and quadrupole field energies. The dipole axis orientation is constant during Parker’s 23rd and 24th encounters.
Rivera, Yeimy J., Finley, Adam J., Badman, Samuel T., Panasenco, Olga A., Klein, Kristopher G., Das, Srijan Bharati et al. · arXiv:2611.12416v1 · Figure 1: · CC BY 4.0
Parker’s rapid sampling within a few days covered almost the entire range of magneto‑latitude, effectively providing a “full‑Sun scan” at the inner heliosphere. By comparing the wind speeds, magnetic fields, and mass fluxes versus magneto‑latitude with historic Ulysses observations at both solar minimum and maximum, researchers found that the 2025 data matched the Ulysses dipolar pattern seen at solar minimum. This similarity is shown in Figure 3, where the two‑hemisphere structure—fast wind in each magneto‑latitude sector—matches the dipole‑controlled pattern observed by Ulysses during solar minimum, rather than the disordered mixed‑polarity picture recorded by Ulysses at solar maximum.
Figure 3. Comparison of bulk speed, radial magnetic field, and mass flux versus magneto‑latitude for Parker 2025 (left column) with Ulysses scans at solar minimum and maximum (right column), demonstrating the 2025 dipole‑controlled two‑hemisphere structure resembling the solar‑minimum pattern and contrasting with the mixed‑polarity view at solar maximum.Rivera, Yeimy J., Finley, Adam J., Badman, Samuel T., Panasenco, Olga A., Klein, Kristopher G., Das, Srijan Bharati et al. · arXiv:2611.12416v1 · Figure 3: · CC BY 4.0
These results indicate that even while the solar magnetic cycle is at its peak, the corona can retain an organized, dipole‑dominated topology. The study also notes that fast solar‑wind streams are subtly deformed by non‑dipolar features such as pseudostreamer structures and mass‑flux enhancements at magnetic separatrixes, showing that additional complexity exists beyond the simple dipole picture.
Parker Solar Probe finds the Sun’s corona at peak activity still resembles a simple tilted dipole | arXiv News
