National Aeronautics and Space Administration

Living With A Star

Targeted Research and Technology

Tracking Photospheric Magnetic Footpoints with the Magnetic Induction Equation

ROSES ID: NNH05ZDA001N      Selection Year: 2006      

Program Element: Data, Tools, & Methods

Principal Investigator: Peter Schuck

Affiliation(s): Naval Reseach Laboratory

Project Member(s):
Krall, Jonathan Co-I Naval Research Laboratory
LaBonte, Barry J Collaborator The Johns Hopkins University
Huba, Joseph Collaborator Naval Research Laboratory


We propose a three-year program to develop techniques for accurate and precise estimation of solar surface flows from magnetogram data. Local Correlation Tracking (LCT) is the de-facto standard for estimating motion in solar image sequences. However, this technique has many documented limitations. Perhaps the greatest limitations of LCT are the absence of demonstrated accuracy, precision and a quantifiable local uncertainty associated with the velocities derived from this technique, and the introduction of artificial scales. This program will develop new techniques that are less susceptible to these limitations.

The proposed techniques determine the optical flow by applying the magnetic induction equation and an affine velocity model statistically to a windowed subregion of the magnetogram sequence producing an overdetermined system that can be solved directly by standard least squares or total least squares techniques. These subspace methods are inherently statistical. Consequently, the optical flow estimates can be assessed for reliability and for resolution of the aperture problem. The result is a point-by-point optical flow field that is consistent with the magnetic induction equation. Our new algorithms will be benchmarked against synthetic data to establish the accuracy of the technique and compared against the accuracy of previously developed optical flow techniques such as LCT, Inductive Local Correlation Tracking (ILCT), Minimum Energy Fit (MEF). Our new techniques will make full use of high-resolution, high-cadence vector magnetogram data and line-of-sight magnetograms for the dual purposes of scientific analysis and and to augment space-weather prediction through real-time monitoring of photospheric activity. The output of this program with be the new methods and the extensively documented performance characteristics of the algorithm. Furthermore, magnetograms will be analyzed and the estimated velocity fields and associated uncertainties will be provided to the solar physics community for the purpose of driving realistic MHD simulations. The prime measure of success for this work would be the widespread use of these ``tools'' for the determination of solar surface flows from observational data. Therefore, the library of tools developed under the program will be accessible to the solar physics community.

This program addresses the goals of the ``Tools and Methods'' component of the Living with a Star (LWS) Targeted Research and Technology Program (TR & T). The goal of our program is to develop the tools and scientific understanding needed for the United States to effectively address those aspects of the Sun-Earth System that may affect life and society. The proposed work will provide the necessary tools to deliver significant new understanding of solar eruptions and resolve persistent controversies concerning the spatial scales and flow velocities.


Performance YearReferenceInvestigation TypeActions
1Schuck, P. W.; (2006), Tracking Magnetic Footpoints with...
not set
1Schuck, P. W.; (2008), Tracking Vector Magnetograms wit...
not set
1Welsch, Brian T.; Li, Yan; Schuck, Peter W.; Fisher,...
not set


Performance YearReferenceActions
1Schuck, Peter W.; (2006), Tracking Magnetic Footpoints in ...
1Schuck, P. W.; (2008), Tracking Vector Magnetograms with ...
1Welsch, Brian; Li, Y.; Schuck, P. W.; Fisher, G. H....
1Welsch, B. T.; Li, Y.; Schuck, P. W.; Fisher, G. H...

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