Time Series Analysis of Photospheric Magnetic Parameters of Flare-Quiet Versus Flaring Active Regions: Scaling Propertie
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Time Series Analysis of Photospheric Magnetic Parameters of Flare-Quiet Versus Flaring Active Regions: Scaling Properties of Fluctuations Eo-Jin Lee1 · Sung-Hong Park2 Yong-Jae Moon1,3
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Received: 25 February 2020 / Accepted: 16 August 2020 © Springer Nature B.V. 2020
Abstract Time series of photospheric magnetic parameters of solar active regions (ARs) are used to answer the question whether scaling properties of fluctuations embedded in such time series help to distinguish between flare-quiet and flaring ARs. We examine a total of 118 flare-quiet and 118 flaring AR patches, Helioseismic and Magnetic Imager Active Region Patches (called HARPs), which were observed from 2010 to 2016 by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO). Specifically, the scaling exponent of fluctuations is derived applying the Detrended Fluctuation Analysis (DFA) method to a dataset of 8-day time series of 18 photospheric magnetic parameters at 12-min cadence for all HARPs under investigation. We first find a statistically significant difference in the distribution of the scaling exponent between the flare-quiet and flaring HARPs, in particular for some space-averaged, signed parameters associated with magnetic field line twist, electric current density, and current helicity. The flaring HARPs tend to show higher values of the scaling exponent compared to those of the flare-quiet ones, even though there is considerable overlap between their distributions. In addition, for both the flare-quiet and the flaring HARPs the DFA analysis indicates that i) time series of most of various magnetic parameters under consideration are non-stationary, and ii) time series of the total unsigned magnetic flux and the mean photospheric magnetic free energy density in general present a non-stationary, persistent property, while the total unsigned flux near magnetic polarity inversion lines and parameters related to current density show a non-stationary, anti-persistent trend in their time series.
B S.-H. Park
[email protected] E.-J. Lee [email protected] Y.-J. Moon [email protected]
1
School of Space Research, Kyung Hee University, Yongin, Republic of Korea
2
Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Nagoya, Japan
3
Department of Astronomy and Space Science, Kyung Hee University, Yongin, Republic of Korea
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Keywords Active regions, magnetic fields · Flares, relation to magnetic field
1. Introduction Solar active regions (ARs) have been intensively studied in the last few decades in the context of how their magnetic field properties are related to flare productivity, mainly using a snapshot of a photospheric line-of-sight or vector magnetogram (e.g. Leka and Barnes, 2003, 2007; Georgoulis and Rust, 2007; Falconer et al., 2011; Bobra and Couvidat, 2015; Toriumi et al., 2017), as well as a sequence of magnetograms over an interval of a few hours to days (e.g. Welsch et al., 2009; Park et al., 2008; Park, Chae, and Wang, 201
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