Deciphering solar turbulence from sunspots records

TL;DR

This paper investigates how sunspot records reflect the turbulent magnetic activity inside the Sun, revealing different spectral behaviors during quiescent and active periods and demonstrating strong intermittency similar to solar wind observations.

Contribution

It provides new insights into the turbulent nature of solar magnetic flux through analysis of sunspot and isotope data, highlighting intermittency and spectral scaling variations.

Findings

Different frequency scalings during quiescent and active solar phases

Strong intermittency in sunspot data comparable to solar wind

Power spectral densities reveal turbulence signatures in sunspot records

Abstract

It is generally believed that sunspots are the emergent part of magnetic flux tubes in the solar interior. These tubes are created at the base of the convection zone and rise to the surface due to their magnetic buoyancy. The motion of plasma in the convection zone being highly turbulent, the surface manifestation of sunspots may retain the signature of this turbulence, including its intermittency. From direct observations of sunspots, and indirect observations of the concentration of cosmogenic isotopes $^{14}$C in tree rings or $^{10}$Be in polar ice, power spectral densities in frequency are plotted. Two different frequency scalings emerge, depending on whether the Sun is quiescent or active. %magnetic activity is maximum or minimum. From direct observations we can also calculate scaling exponents. These testify to a strong intermittency, comparable with that observed in the solar wind.