Automated Solar Feature Detection for Space Weather Applications |
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David Perez-Suarez Submitted: 2011-10-05 20:15
The solar surface and atmosphere are highly dynamic plasma environments, which evolve over a wide range of temporal and spatial scales. Large-scale eruptions, such as coronal mass ejections, can be accelerated to millions of kilometres per hour in a matter of minutes, making their automated detection and characterisation challenging. Additionally, there are numerous faint solar features, such as coronal holes and coronal dimmings, which are important for space weather monitoring and forecasting, but their low intensity and sometimes transient nature makes them problematic to detect using traditional image processing techniques. These difficulties are compounded by advances in ground- and space- based instrumentation, which have increased the volume of data that solar physicists are confronted with on a minute-by-minute basis; NASA's Solar Dynamics Observatory for example is returning many thousands of images per hour (~1.5 TB/day). This chapter reviews recent advances in the application of images processing techniques to the automated detection of active regions, coronal holes, filaments, CMEs, and coronal dimmings for the purposes of space weather monitoring and prediction.
Authors: David Perez-Suarez, Paul A. Higgins, D. Shaun Bloomfield, R.T. James McAteer, Larisza D. Krista, Jason P. Byrne, Peter. T. Gallagher
Projects: SDO-AIA
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Publication Status: Book chapter in -Applied Signal and Image Processing: Multidisciplinary Advancements- (ed. Rami Qahwaji, Roger Green and Evor L. Hines) pp. 207-225
Last Modified: 2011-10-05 20:15
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The Structure and Dynamics of a Bright Point as seen with Hinode, SoHO and TRACE |
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David Perez-Suarez Submitted: 2008-10-09 08:49
Our aim is to determine the plasma properties of a coronal
bright point
and compare its magnetic topology extrapolated from magnetogram data
with its appearance in X-ray images.
We analyse spectroscopic data obtained with EIS/Hinode, Ca II H and
G-band images from SOT/Hinode, UV images from TRACE, X-ray images from
XRT/Hinode and high-resolution/high-cadence magnetogram data from MDI/SoHO.
The BP comprises several coronal loops as seen in the X-ray images,
while the chromospheric structure consists of tens of small bright
points as seen in Ca II H. An excellent correlation exists between the
Ca II BPs and increases in the magnetic field, implying that the Ca II H
passband is a good indicator for the concentration of magnetic
flux. Doppler velocities between 6 and 15 km s-1 are derived from the
Fe XII and Fe XIII lines for the BP region, while for
Fe XIV and Si VII
they are in the range from -15 to +15 km s-1. The coronal electron density is
3.7 imes109 cm-3. An excellent correlation is found between
the positive magnetic flux and the X-ray light-curves.
The remarkable agreement between the extrapolated magnetic field
configuration and some of the loops composing the BP as
seen in the X-ray images suggests that a large fraction of the
magnetic field in the bright point is close to potential. The close
correlation between the positive magnetic flux and the X-ray emission
suggests that energy released by magnetic reconnection is stimulated by
flux emergence or cancellation.
Authors: D. P'erez-Su'arez, R.C. Maclean, J.G. Doyle and M.S. Madjarska
Projects: Hinode/EIS,Hinode/SOT,Hinode/XRT,SoHO-EIT,SoHO-MDI,TRACE
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Publication Status: A&A (in press)
Last Modified: 2008-10-09 08:49
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