The Sun

Understanding and predicting solar magnetism is critical for safeguarding satellites, planning space missions and mitigating the effects of space weather on modern infrastructure. However, the physical processes governing the solar cycle remain elusive. Here, applying methods of helioseismology on observations taken by the Helioseismic and Magnetic Imager, we report the possible detection of global magnetized inertial dispersions, a slow mode and a weaker, retrograde feature possibly consistent with the fast mode, whose dynamics are theorized to modulate the solar dynamo. These modes appear to be confined to layers r/R⊙≲ 0.98, exhibit amplitudes weaker than those of hydrodynamic Rossby waves and resonate at frequencies consistent with the presence of an effective large-scale toroidal magnetic field of strength ∼5ρ/ρS Gauss, where ρ is density and ρS ≈ 4 × 10−7g cm−3 is the surface density. If the toroidal field were to be located at the base of the convection zone (ρ ≈ 0.44 g cm−3), its amplitude would be \~5 × 103 G, consistent with helioseismic and other estimates. By mapping these motions in the surface layers, we uncover a window into the magnetic architecture of the Sun, offering a potential path towards more accurate forecasts of solar activity.