Examination of artifact in vector magnetic field SDO/HMI measurements

TL;DR

This study identifies a systematic error in SDO/HMI vector magnetic data, showing deviation of magnetic field lines from radial direction depending on disk position, and proposes a correction method to improve data accuracy.

Contribution

It introduces a correction method for systematic errors in SDO/HMI vector magnetograms based on observed deviations.

Findings

Detected significant deviation of magnetic field lines from radial direction.

Deviation depends on distance to disk center.

Proposed correction method effectively eliminates the systematic error.

Abstract

In this paper, we came to conclusion that there is a significant systematic error in the SDO/HMI vector magnetic data, which reveals itself in a significant deviation of the lines of the knot magnetic fields from the radial direction. The value of this deviation demonstrates a clear dependence on the distance to the disk center. This paper suggests a method for correction of the vector magnetograms that eliminates the detected systematic error.