The total solar irradiance, UV emission and magnetic flux during the last solar cycle minimum

TL;DR

This study analyzes the relationship between total solar irradiance, UV emission, and magnetic flux during the last solar cycle minimum, revealing in-phase structures and magnetic flux dynamics linked to solar activity complexes.

Contribution

It provides new insights into the connection between magnetic flux, TSI, and UV emissions during a deep solar minimum, highlighting the role of long-lived magnetic activity complexes.

Findings

Increase in magnetic flux correlates with TSI and UV during surface rotation timescales.

In-phase structures between magnetic flux and irradiance are linked to long-lived activity complexes.

A phase lead of magnetic flux over TSI was observed during the deep minimum.

Abstract

We have analyzed the total solar irradiance (TSI) and the spectral solar irradiance as ultraviolet emission (UV) in the wavelength range 115-180 nm, observed with the instruments TIM and SOLSTICE within the framework of SORCE (The Solar Radiation and Climate Experiment) during the long solar minimum between the 23rd and 24th cycles. The wavelet analysis reveals an increase in the magnetic flux in the latitudinal zone of the sunspot activity, accompanied with an increase in the TSI and UV on the surface rotation timescales of solar activity complexes. In-phase coherent structures between the mid-latitude magnetic flux and TSI/UV appear when the long-lived complexes of the solar activity are present. These complexes, which are related to long- lived sources of magnetic fields under the photosphere, are maintained by magnetic fluxes reappearing in the same longitudinal regions. During the deep solar minimum (the period of the absence of sunspots) a coherent structure has been found, in which the phase between the integrated mid-latitude magnetic flux is ahead of the total solar irradiance on the timescales of the surface rotation.