2D Feature Recognition And 3d Reconstruction In Solar Euv Images

EUV images show the solar corona in a typical temperature range of T >rsim 1 MK, which encompasses the most common coronal structures: loops, filaments, and other magnetic structures in active regions, the quiet Sun, and coronal holes. Quantitative analysis increasingly demands automated 2D feature recognition and 3D reconstruction, in order to localize, track, and monitor the evolution of such coronal structures. We discuss numerical tools that “fingerprint” curvi-linear 1D features (e.g., loops and filaments). We discuss existing finger-printing algorithms, such as the brightness-gradient method, the oriented-connectivity method, stereoscopic methods, time-differencing, and space–time feature recognition. We discuss improved 2D feature recognition and 3D reconstruction techniques that make use of additional a priori constraints, using guidance from magnetic field extrapolations, curvature radii constraints, and acceleration and velocity constraints in time-dependent image sequences. Applications of these algorithms aid the analysis of SOHO/EIT, TRACE, and STEREO/SECCHI data, such as disentangling, 3D reconstruction, and hydrodynamic modeling of coronal loops, postflare loops, filaments, prominences, and 3D reconstruction of the coronal magnetic field in general.

[1]  Y.-M. Wang.  EIT Waves and Fast-Mode Propagation in the Solar Corona , 2000 .

[2]  M. Aschwanden.  Physics of the Solar Corona. An Introduction , 2004 .

[3]  Joseph B. Gurman,et al.  Observation of Quasi-periodic Compressive Waves in Solar Polar Plumes , 1998 .

[4]  M. Aschwanden,et al.  VLA stereoscopy of solar active regions. 1: Method and tests , 1994 .

[5]  Haimin Wang,et al.  Temperatures of Extreme-Ultraviolet-emitting Plasma Structures Observed by the Transition Region and Coronal Explorer , 2002 .

[6]  S. Solanki,et al.  Vertical oscillations of a coronal loop observed by TRACE , 2004 .

[7]  R. Canfield,et al.  Is the solar chromospheric magnetic field force-free? , 1995 .

[8]  Jean-Pierre Delaboudiniere,et al.  Three-dimensional Stereoscopic Analysis of Solar Active Region Loops. I. SOHO/EIT Observations at Temperatures of (1.0-1.5) × 106 K , 1999 .

[9]  T. Wiegelmann.  Optimization code with weighting function for the reconstruction of coronal magnetic fields , 2008, 0802.0124.

[10]  G. A. Gary,et al.  Plasma Beta above a Solar Active Region: Rethinking the Paradigm , 2001 .

[11]  A. Pevtsov,et al.  On the Subphotospheric Origin of Coronal Electric Currents , 1997 .

[12]  T. Neukirch,et al.  Including stereoscopic information in the reconstruction of coronal magnetic fields , 2002, 0801.3234.

[13]  G. A. Gary,et al.  Eruption of a Multiple-Turn Helical Magnetic Flux Tube in a Large Flare: Evidence for External and Internal Reconnection That Fits the Breakout Model of Solar Magnetic Eruptions , 2004 .

[14]  M. Karovska,et al.  Comparison of Two Coronal Mass Ejections Observed by EIT and LASCO with a Model of an Erupting Magnetic Flux Rope , 1999 .

[15]  B. Inhester,et al.  Magnetic modeling and tomography: First steps towards a consistent reconstruction of the solar corona , 2003 .

[16]  C. J. Wolfson,et al.  Time Variability of the “Quiet” Sun Observed with TRACE. I. Instrumental Effects, Event Detection, and Discrimination of Extreme-Ultraviolet Microflares , 2000 .

[17]  J. B. Gurman,et al.  SOHO/EIT observations of an Earth‐directed coronal mass ejection on May 12, 1997 , 1998 .

[18]  B. Thompson,et al.  Cradle to grave tracking of the January 6–11,1997 Sun‐Earth connection event , 1998 .

[19]  M. Aschwanden,et al.  VLA stereoscopy of solar active regions. 2: Altitude, relative motion, and center-to-limb darkening of 20 centimeter emission , 1994 .

[20]  Bart De Pontieu,et al.  Transverse Oscillations in Coronal Loops Observed with TRACE – II. Measurements of Geometric and Physical Parameters , 2002 .

[21]  Carolus J. Schrijver,et al.  Coronal Loop Oscillations Observed with the Transition Region and Coronal Explorer , 1999 .