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arXiv · 2211.08323

The Universality of Power Law Slopes in the Solar Photosphere and Transition Region Observed with HMI and IRIS

Markus J. Aschwanden·Nived Vilangot Nhalil
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Abstract

We compare the size distributions of self-organized criticality (SOC) systems in the solar photosphere and the transition region, using magnetogram data from Helioseismic and Magnetic Imager (HMI) and Interface Region Imaging Spectrograph (IRIS)} data. For each dataset we fit a combination of a Gaussian and a power law size distribution function, which yields information on four different physical processes: (i) Gaussian random noise in IRIS data; (ii) spicular events in the plages of the transition region (described by power law size distribution in IRIS data); (iii) salt-and-pepper small-scale magnetic structures (described by the random noise in HMI magnetograms); and (iv) magnetic reconnection processes in flares and nanoflares (described by power law size distributions in HMI data). We find a high correlation (CCC=0.90) between IRIS and HMI data. Datasets with magnetic flux balance are generally found to match the SOC-predicted power law slope a_F=1.80 (for mean fluxes F), but exceptions occur due to arbitrary choices of the HMI field-of-view. The matching cases confirm the universality of SOC-inferred flux size distributions, and agree with the results of Parnell et al.~(2009), a_F=1.85 +/- 0.14.

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Markus J. Aschwanden, Nived Vilangot Nhalil. 2022-11-15. The Universality of Power Law Slopes in the Solar Photosphere and Transition Region Observed with HMI and IRIS. https://arxiv.org/abs/2211.08323

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