Multiresolution Analysis of Active Region Magnetic Structure and its Correlation with the Mount Wilson Classification and Flaring Activity |
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| Authors: | J Ireland C A Young R T J McAteer C Whelan R J Hewett P T Gallagher |
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| Institution: | (1) ADNET Systems, Inc., NASA’s Goddard Spaceflight Center, Mail Code 671.1, Greenbelt, MD 20771, USA;(2) Catholic University of America, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA;(3) School of Physics, University College Dublin, Belfield, Dublin 4, Ireland;(4) Computer Science Department, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA;(5) Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2, Ireland |
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| Abstract: | Two different multiresolution analyses are used to decompose the structure of active-region magnetic flux into concentrations
of different size scales. Lines separating these opposite polarity regions of flux at each size scale are found. These lines
are used as a mask on a map of the magnetic field gradient to sample the local gradient between opposite polarity regions
of given scale sizes. It is shown that the maximum, average, and standard deviation of the magnetic flux gradient for α,β,β
γ, and β
γ
δ active-regions increase in the order listed, and that the order is maintained over all length scales. Since magnetic flux
gradient is strongly linked to active-region activity, such as flares, this study demonstrates that, on average, the Mt. Wilson
classification encodes the notion of activity over all length scales in the active-region, and not just those length scales
at which the strongest flux gradients are found. Further, it is also shown that the average gradients in the field, and the
average length-scale at which they occur, also increase in the same order. Finally, there are significant differences in the
gradient distribution, between flaring and non-flaring active regions, which are maintained over all length scales. It is
also shown that the average gradient content of active-regions that have large flares (GOES class “M” and above) is larger
than that for active regions containing flares of all flare sizes; this difference is also maintained at all length scales.
All of the reported results are independent of the multiresolution transform used. The implications for the Mt. Wilson classification
of active-regions in relation to the multiresolution gradient content and flaring activity are discussed. |
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| Keywords: | Sun: active region Sun: magnetic field |
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