The Sun's Magnetic Power Spectra over Two Solar Cycles. \uppercase\expandafter{\romannumeral2}. Cycle Dependence of Active Region, Magnetic Network, and Their Relation

TL;DR

This study analyzes the cycle-dependent properties of solar magnetic components, revealing that magnetic network power varies weakly with solar activity and remains stable without sunspots, providing insights for modeling the solar magnetic field.

Contribution

It introduces a new method to analyze magnetic power spectra, highlighting the cycle dependence of active regions and magnetic network, and their relation across solar cycles.

Findings

Magnetic network size ranges from 26 Mm to 41 Mm, independent of the solar cycle.

Network power accounts for about 20% of total magnetic power, with weak cycle dependence.

Magnetic power spectra are stable and similar in shape when no sunspots are present.

Abstract

The multi-scaled solar magnetic field consists of two major components: active regions (ARs) and magnetic network. Unraveling the cycle-dependent properties and interrelations of these components is crucial for understanding the evolution of the solar magnetic field. In this study, we investigate these components using magnetic power spectra derived from high-resolution and continuous synoptic magnetograms since cycle 23 onwards. Our results show that the size of the magnetic network ranges from 26 Mm to 41 Mm without dependence on the solar cycle. The power of the network field ($P_{NW}$) accounts for approximately 20\% of the total power during any phase of solar cycles. In contrast to the AR power ($P_{AR}$), $P_{NW}$ displays a weaker cycle dependence, as described by the relationship $P_{NW}$ $\approx$ 0.6* $P_{AR}$ + 40. The power-law index between AR sizes and magnetic network sizes presents a strong anti-correlation with the activity level. Additionally, our study indicates that in the absence of sunspots on the solar disc, the magnetic power spectra remain time-independent, consistently exhibiting similarity in both shape and power. This study introduces a new method to investigate the properties of the magnetic network and provides magnetic power spectra for high-resolution simulations of the solar magnetic field at the surface at various phases of solar cycles.