The Effect of Limited Sample Sizes on the Accuracy of the Estimated Scaling Parameter for Power-Law-Distributed Solar Data

Abstract

Many natural processes exhibit power-law behavior. The power-law exponent is linked to the underlying physical process and therefore its precise value is of interest. With respect to the energy content of nanoflares, for example, a power-law exponent steeper than 2 is believed to be a necessary condition to solve the enigmatic coronal heating problem. Studying power-law distributions over several orders of magnitudes requires sufficient data and appropriate methodology. In this paper we demonstrate the shortcomings of some popular methods in solar physics that are applied to data of typical sample sizes. We use synthetic data to study the effect of the sample size on the performance of different estimation methods and show that vast amounts of data are needed to obtain a reliable result with graphical methods (where the power-law exponent is estimated by a linear fit on a log-transformed histogram of the data). We revisit published results on power laws for the angular width of solar coronal mass ejections and the radiative losses of nanoflares. We demonstrate the benefits of the maximum likelihood estimator and advocate its use.

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Cited by in corpus (8)

• Stellar Coronal Mass Ejections I. Estimating occurrence frequencies and mass-loss rates
• Effects of flare definitions on the statistics of derived flare distributions
• Investigating width distribution of slow and fast CMEs in solar cycles 23 and 24
• Is the Hemispheric Asymmetry of Monthly Sunspot Area an Irregular Process with Long-Term Memory?
• A Coronal Mass Ejection Source Region Catalogue and their Associated Properties
• Power-law Distribution of Solar-Cycle Modulated Coronal Jets
• Coronal Heating as Determined by the Solar Flare Frequency Distribution Obtained by Aggregating Case Studies
• Power-law Indices of EUV Intensity Power Spectrum in Flaring Coronal Active Regions