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A Database of Flare Ribbon Properties from the Solar Dynamics Observatory. I. Reconnection Flux  

Maria D Kazachenko   Submitted: 2017-08-30 12:43

We present a database of 3137 solar flare ribbon events corresponding to every flare of GOES class C1.0 and greater within 45? from the central meridian, from 2010 April until 2016 April, observed by the Solar Dynamics Observatory. For every event in the database, we compare the GOES peak X-ray flux with the corresponding active region and flare ribbon properties. We find that while the peak X-ray flux is not correlated with the active region unsigned magnetic flux, it is strongly correlated with the flare ribbon reconnection flux, flare ribbon area, and the fraction of active region flux that undergoes reconnection. We find the relationship between the peak X-ray flux and the flare ribbon reconnection flux to be IX,peak ~ (Φribbon)1.5. This scaling law is consistent with earlier hydrodynamic simulations of impulsively heated flare loops. Using the flare reconnection flux as a proxy for the total released flare energy E, we find that the occurrence frequency of flare energies follows a power-law dependence: dN/dE~E-1.6 for 1d31< E< 1d33 erg, consistent with earlier studies of solar and stellar flares. The database is available online and can be used for future quantitative studies of flares.

Authors: Kazachenko, Maria D.; Lynch, Benjamin J.; Welsch, Brian T.; Sun, Xudong
Projects: GOES X-rays,SDO-AIA,SDO-HMI

Publication Status: The Astrophysical Journal, Volume 845, Issue 1, article id. 49, 13 pp. (2017).
Last Modified: 2017-08-30 13:42
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Photospheric Electric Fields and Energy Fluxes in the Eruptive Active Region NOAA 11158  

Maria D Kazachenko   Submitted: 2015-08-17 12:26

How much electromagnetic energy crosses the photosphere in evolving solar active regions? With the advent of high-cadence vector magnetic field observations, addressing this fundamental question has become tractable. In this paper, we apply the "PTD-Doppler-FLCT-Ideal" (PDFI) electric field inversion technique of Kazachenko et al. (2014) to a 6-day HMI/SDO vector magnetogram and Doppler velocity sequence, to find the electric field and Poynting flux evolution in active region NOAA 11158, which produced an X2.2 flare early on 2011 February 15. We find photospheric electric fields ranging up to 2 V/cm. The Poynting fluxes range from [-0.6 to 2.3]*1010 ergs cm-2 s-1, mostly positive, with the largest contribution to the energy budget in the range of [109-1010] ergs cm-2 s-1. Integrating the instantaneous energy flux over space and time, we find that the total magnetic energy accumulated above the photosphere from the initial emergence to the moment before the X2.2 flare to be E=10.6*1032 ergs, which is partitioned as 2.0 and 8.6*1032 ergs, respectively, between free and potential energies. Those estimates are consistent with estimates from preflare non-linear force-free field (NLFFF) extrapolations and the Minimum Current Corona estimates (MCC), in spite of our very different approach. This study of photospheric electric fields demonstrates the potential of the PDFI approach for estimating Poynting fluxes and opens the door to more quantitative studies of the solar photosphere and more realistic data-driven simulations of coronal magnetic field evolution.

Authors: Kazachenko, Maria D.; Fisher, George H.; Welsch, Brian T.; Liu, Yang; Sun, Xudong
Projects: SDO-HMI

Publication Status: 51 pages, 10 figures, accepted by ApJ on August 11, 2015
Last Modified: 2015-08-17 15:10
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The Coronal Global Evolutionary Model (CGEM): Using HMI Vector Magnetogram and Doppler Data to Model the Buildup of Free Magnetic Energy in the Solar Corona  

Maria D Kazachenko   Submitted: 2015-06-01 13:29

The most violent space weather events (eruptive solar flares and coronal mass ejections) are driven by the release of free magnetic energy stored in the solar corona. Energy can build up on timescales of hours to days, and then may be suddenly released in the form of a magnetic eruption, which then propagates through interplanetary space, possibly impacting the Earth's space environment. Can we use the observed evolution of the magnetic and velocity fields in the solar photosphere to model the evolution of the overlying solar coronal field, including the storage and release of magnetic energy in such eruptions? The objective of CGEM, the Coronal Global Evolutionary Model, funded by the NASA/NSF Space Weather Modeling program, is to develop and evaluate such a model for the evolution of the coronal magnetic field. The evolving coronal magnetic field can then be used as a starting point for magnetohydrodynamic (MHD) models of the corona, which can then be used to drive models of heliospheric evolution and predictions of magnetic field and plasma density conditions at 1AU.

Authors: Fisher, George H.; Abbett, William. P.; Bercik, David J.; Kazachenko, Maria D.; Lynch, Benjamin J.; Welsch, Brian T.; Hoeksema, J. Todd; Hayashi, Keiji; Liu, Yang; Norton, Aimee A.; Sainz Dalda, Alberto; Sun, Xudong; DeRosa, Marc L.; Cheung, Mark C. M.
Projects: SDO-HMI

Publication Status: 7 pages, 2 figures. Accepted for publication by
Last Modified: 2015-06-04 05:41
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Predictions of Energy and Helicity in Four Major Eruptive Solar Flares  

Maria D Kazachenko   Submitted: 2011-07-21 12:14

This abstract was corrupted following database problems and is being recovered. It will be restored as quickly as possible. Any questions, please send them to Alisdair. Sorry for any incovenience.


Authors: Maria D. Kazachenko, Richard C. Canfield, Dana W. Longcope, Jiong Qiu
Projects: SoHO-MDI,TRACE

Publication Status: published in Solar Physics 07/2011
Last Modified: 2011-07-26 09:23
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Sunspot Rotation, Flare Energetics and Flux Rope Helicity: The Halloween Flare on 2003 October 28  

Maria D Kazachenko   Submitted: 2010-08-27 13:38

We study the X17 eruptive flare on 2003 October 28 using MDI observations of photospheric magnetic and velocity fields and TRACE 1600A images of the flare in a three-dimensional model of energy buildup and release in NOAA 10486. The most dramatic feature of this active region is the 123 degrees rotation of a large positive sunspot over 46 hr prior to the event. We apply a method for including such rotation in the framework of the Minimum Current Corona model (MCC, Longcope 1996) of the buildup of energy and helicity due to the observed motions. We distinguish between helicity and energy stored in the whole active region and that released in the flare itself. We find that while the rotation of a sunspot contributes significantly to the energy and helicity budgets of the whole active region, it makes only a minor contribution to that part of the region that flares. We conclude that in spite of the fast rotation, shearing motions alone store sufficient energy and helicity to account for the flare energetics and ICME helicity content within their observational uncertainties. Our analysis demonstrates that the relative importance of shearing and rotation in this flare depends critically on their location within the parent active region topology.

Authors: Maria D. Kazachenko, Richard C. Canfield, Dana W. Longcope, Jiong Qiu
Projects: SoHO-MDI,TRACE

Publication Status: accepted for publication in ApJ
Last Modified: 2010-08-29 18:30
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Sunspot Rotation, Flare Energetics and Flux Rope Helicity: The Eruptive Flare on 2005 May 13  

Maria D Kazachenko   Submitted: 2009-09-15 22:42

We use MDI and TRACE observations of photospheric magnetic and velocity fields in NOAA 10759 to build a three-dimensional coronal magnetic field model. The most dramatic feature of this active region is the 34 degree rotation of its leading polarity sunspot over 40 hours. We describe a method for including such rotation in the framework of the minimum current corona (MCC) model. We apply this method to the buildup of energy and helicity associated with the eruptive flare of 2005 May 13. We find that including the sunspot rotation almost triples the modeled flare energy (1.0 imes1031ergs) and flux rope self helicity (-7.1 imes1042, { m Mx}^2). This makes the results consistent with observations: the energy derived from GOES is 1.0 imes1031ergs, the magnetic cloud helicity from WIND is -5 imes1042, { m Mx}^2. Our combined analysis yields the first quantitative picture of the helicity and energy content processed through a flare in an active region with an obviously rotating sunspot and shows that rotation dominates the energy and helicity budget of this event.

Authors: Maria D. Kazachenko, Richard C. Canfield, Dana W. Longcope, Jiong Qiu, Angela DesJardins, Richard W. Nightingale
Projects: SoHO-MDI,TRACE

Publication Status: accepted for publication in ApJ
Last Modified: 2009-09-16 08:00
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Abstracts by Author
A Database of Flare Ribbon Properties from the Solar Dynamics Observatory. I. Reconnection Flux
Photospheric Electric Fields and Energy Fluxes in the Eruptive Active Region NOAA 11158
The Coronal Global Evolutionary Model (CGEM): Using HMI Vector Magnetogram and Doppler Data to Model the Buildup of Free Magnetic Energy in the Solar Corona
Predictions of Energy and Helicity in Four Major Eruptive Solar Flares
Sunspot Rotation, Flare Energetics and Flux Rope Helicity: The Halloween Flare on 2003 October 28
Sunspot Rotation, Flare Energetics and Flux Rope Helicity: The Eruptive Flare on 2005 May 13

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