TITLE:
Hough Transform to Study the Magnetic Confinement of Solar Spicules
AUTHORS:
E. Tavabi, S. Koutchmy, A. Ajabshirizadeh
KEYWORDS:
Solar Chromosphere; Spicule; Hough Transform; Tracing; Magnetic Focusing
JOURNAL NAME:
Journal of Modern Physics,
Vol.3 No.11,
November
28,
2012
ABSTRACT: One of the important parameters of the ubiquitous spicules rising intermittently above the surface of the Sun is the variation of spicule spline orientation with respect to the solar coordinates, presumably reflecting the focusing of ejection by the coronal magnetic field. Here we first use a method of tracing limb spicules using a combination of second derivative operators in multiple directions around each pixel to enhance the visibility of fine linear part of spicules. Furthermore, the Hough transform is used for a statistical analysis of spicule orientations in different regions around the solar limb, from the pole to the equator. Our results show a large difference of spicule apparent tilt angles in regions of: 1) the solar poles, 2) the equator, 3) the active regions and 4) the coronal holes. Spicules are visible in a radial direction in polar regions with a tilt angle