Active Region Photospheric Magnetic Properties Derived from Line-of-sight and Radial Fields

Abstract

The effect of using two representations of the normal-to-surface magnetic field to calculate photospheric measures that are related to active region (AR) potential for flaring is presented. Several AR properties were computed using line-of-sight ($B_{\mathrm{los}}$) and spherical-radial ($B_r$) magnetograms from the Space-weather HMI Active Region Patch (SHARP) products of the \emph{Solar Dynamics Observatory}, characterizing the presence and features of magnetic polarity inversion lines, fractality, and magnetic connectivity of the AR photospheric field. The data analyzed corresponds to $\approx$ 4,000 AR observations, achieved by randomly selecting 25 % of days between September 2012 and May 2016 for analysis at 6-hr cadence. Results from this statistical study include: i) the $B_r$ component results in a slight upwards shift of property values in a manner consistent with a field-strength underestimation by the $B_{\mathrm{los}}$ component; ii) using the $B_r$ component results in significantly lower inter-property correlation in one-third of the cases, implying more independent information about the state of the AR photospheric magnetic field; iii) flaring rates for each property vary between the field components in a manner consistent with the differences in property-value ranges resulting from the components; iv) flaring rates generally increase for higher values of properties, except Fourier spectral power index that has flare rates peaking around a value of $5/3$. These findings indicate that there may be advantages in using $B_r$ rather than $B_{\mathrm{los}}$ in calculating flare-related AR magnetic properties, especially for regions located far from central meridian.

References in corpus (7)

• Torus instability
• The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: SHARPs -- Space-weather HMI Active Region Patches
• The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Overview and Performance
• Global Energetics of Solar Flares: V. Energy Closure in Flares and Coronal Mass Ejections
• An automated classification approach to ranking photospheric proxies of magnetic energy build-up
• Evaluating (and Improving) Estimates of the Solar Radial Magnetic Field Component from Line-of-Sight Magnetograms
• A new method to quantify and reduce projection error in whole-solar-active-region parameters measured from vector magnetograms

Cited by in corpus (5)

• Flare Forecasting Algorithms Based on High-Gradient Polarity Inversion Lines in Active Regions
• Leveraging the Mathematics of Shape for Solar Magnetic Eruption Prediction
• The characteristics of flare- and CME-productive solar active regions
• Machine learning as a flaring storm warning machine: Was a warning machine for the September 2017 solar flaring storm possible?
• Near-continuous tracking of solar active region NOAA 13664 over three solar rotations