What the sudden death of solar cycles can tell us about the nature of the solar interior

Abstract

We observe the abrupt end of solar activity cycles at the Sun's equator by combining almost 140 years of observations from ground and space. These "terminator" events appear to be very closely related to the onset of magnetic activity belonging to the next sunspot cycle at mid-latitudes and the polar-reversal process at high-latitudes. Using multi-scale tracers of solar activity we examine the timing of these events in relation to the excitation of new activity and find that the time taken for the solar plasma to communicate this transition is of the order of one solar rotation, but could be shorter. Utilizing uniquely comprehensive solar observations from the Solar Terrestrial Relations Observatory (STEREO), and Solar Dynamics Observatory (SDO) we see that this transitional event is strongly longitudinal in nature. Combined, these characteristics imply that magnetic information is communicated through the solar interior rapidly. A range of possibilities exist to explain such behavior: the presence of magnetic reconnection in the deep interior, internal gravity waves on the solar tachocline, or that the magnetic fields present in the Sun's convection zone could be very large, with a poloidal field strengths reaching 50k - considerably larger than conventional explorations of solar and stellar dynamos estimate. Regardless of mechanism responsible, the rapid timescales demonstrated by the Sun's global magnetic field reconfiguration present strong constraints on first-principles numerical simulations of the solar interior and, by extension, other stars.

arXiv commentSubmitted [10/2017] to, and rejected [01/2019] by, Nature Astronomy. Accepted Solar Physics [6/1/2019]

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Cited by in corpus (10)

• The Solar Orbiter mission -- Science overview
• Overlapping Magnetic Activity Cycles and the Sunspot Number: Forecasting Sunspot Cycle 25 Amplitude
• Timing Terminators: Forecasting Sunspot Cycle 25 Onset
• Deciphering Solar Magnetic Activity: 140 Years Of The `Extended Solar Cycle' -- Mapping the Hale Cycle
• The Extended Solar Cycle and Asymmetry of the Large-Scale Magnetic Field
• Seismic differences between solar magnetic cycles 23 and 24 for low-degree modes
• The High Inclination Solar Mission
• The Sun's magnetic (Hale) cycle and 27 day recurrences in the $aa$ geomagnetic index
• A Revised 27-day Recurrence Index
• A new view of the solar interface region from the Interface Region Imaging Spectrograph (IRIS)