Evolution of the Global Temperature Structure of the Solar Corona During the Minimum between Solar Cycles 23 and 24

• Autores: Nuevo, Federico Alberto; Huang, Zhenguang; Frazin, Richard A.; Manchester IV, Ward B.; Jin, Meng; Vasquez, Alberto Marcos
• Año de publicación: 2013
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: © 2013. The American Astronomical Society.
• Materia: Sun: Corona; Sun: Magnetic Topology; Sun: Uv Radiation; Sun: Evolution - Sunspots
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

The combination of Differential Emission Measure Tomography (DEMT) with extrapolation of the photospheric magnetic field allows determinatio/n of the electron density and electron temperature along individual magnetic field lines. This is especially useful in quiet Sun (QS) plasmas where individual loops cannot otherwise be identified. In Paper I (Huang et al. 2012), this approach was applied to study QS plasmas during Carrington rotation (CR) 2077, at the minimum between solar cycles (SC)-23 and 24. In that work, two types of quiet QS coronal loops were identified: ``up" loops in which the temperature increases with height, and ``down" loops in which the temperature decreases with height. While the first ones were expected, the latter ones were a surprise and, furthermore, were found to be ubiquitous in the low-latitude corona. In the present work we extend the analysis to 11 CRs around the last solar minimum. We find that the ``down´´ population, always located at low-latitudes, was maximum at the time when the sunspot number was minimum, and the number of down loops systematically increased during the declining phase of SC-23 and diminished during the rising phase of SC-24. ``Down´´ loops are found to have systematically larger values of $eta$ than do ``up´´ loops. These discoveries are interpreted in terms of excitation of Alfv´en waves in the photosphere, and mode conversion and damping in the low corona.
Fil: Nuevo, Federico Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio(i); Argentina
Fil: Huang, Zhenguang. Department of Atmospheric, Oceanic and Space Sciences. University of Michigan; Estados Unidos de América;
Fil: Frazin, Richard A.. Department of Atmospheric, Oceanic and Space Sciences. University of Michigan; Estados Unidos de América;
Fil: Manchester IV, Ward B.. Department of Atmospheric, Oceanic and Space Sciences. University of Michigan; Estados Unidos de América;
Fil: Jin, Meng. Department of Atmospheric, Oceanic and Space Sciences. University of Michigan; Estados Unidos de América;
Fil: Vasquez, Alberto Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio(i); Argentina