Comparison of Relative Magnetic Helicity Flux Calculation Results Based on the Line-of-Sight Magnetograms of ASO-S/FMG and SDO/HMI

TL;DR

This study compares magnetic helicity flux calculations from ASO-S/FMG and SDO/HMI line-of-sight magnetograms, demonstrating high consistency and reliability of the new ASO-S data for solar magnetic field analysis.

Contribution

It introduces a method to estimate magnetic helicity flux using ASO-S/FMG data and validates its accuracy against SDO/HMI measurements.

Findings

High correlation (0.98) between ASO-S/FMG and SDO/HMI helicity flux measurements.

Difference in normalized magnetic helicity less than 4%.

Demonstrates reliability of ASO-S/FMG data for future solar magnetic studies.

Abstract

Magnetic helicity is a key geometrical parameter to describe the structure and evolution of solar coronal magnetic fields. The accumulation of magnetic helicity is correlated with the non-potential magnetic field energy, which is released in the solar eruptions. Moreover, the relative magnetic helicity fluxes can be estimated only relying on the line-of-sight magnetic field (e.g., Demoulin and Berger Sol. Phys. 215, 203, 2003). The payload Full-disk MagnetoGraph (FMG) on the Advanced Space-based Solar Observatory (ASO-S) currently has been supplying the continuous evolution of line-of-sight magnetograms for the solar active regions, which can be used to estimate the magnetic helicity flux. In this study, we useeight hours line-of-sight magnetograms of NOAA 13273, when at which the Sun-Earth direction speed of the satellite is zero to avoid the oscillation of the magnetic field caused by the Doppler effect on polarization measurements. We obtain the helicity flux by applying Fast Fourier Transforms (FFT) and local correlation tracking (LCT) methods to obtain the horizontal vector potential field and the motions of the ine-sf-sight polarities. We also compare the helicity flux derived using data from the Heliosesmic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) and the same method. It is found that the flux has the same sign and the correlation between measurements is 0.98. The difference of the absolute magnetic helicity normalized to themagnetic flux is less than 4%. This comparison demonstrates the reliability of ASO-S/FMG data and that it can be reliably used in future studies