Recent studies showed a consistent pattern of changes in the sunspot structure associated with major flares: part of the peripheral penumbral regions vanishes during flares, and meanwhile, the umbral cores and/or inne...Recent studies showed a consistent pattern of changes in the sunspot structure associated with major flares: part of the peripheral penumbral regions vanishes during flares, and meanwhile, the umbral cores and/or inner penumbral regions are darkened. To understand the underlying physics of these observations, we compare the magnetic inclination angle in the decayed peripheral and the enhanced inner penumbral regions before and after the 4B/X3.4 flare of 2006 December 13 by using the high-resolution vector magnetograms from Hinode. We find that the mean inclination angle in the decayed penumbra increases after the flare while that in the enhanced penumbra near flaring neutral line decreases. The result confirms the previous idea that two components of a δ sunspot become connected after flares. As a result of new connection, peripheral penumbral fields change from a more inclined to a more vertical configuration and transverse fields in umbral core and inner penumbral regions increase substantially (Liu et al. 2005). The flare-associated changes of Doppler width as well as other parameters (the transverse field strength, continuum intensity and filling factor) are also presented.展开更多
Three-dimensional (3D) image reconstruction of an Hoc flare near the solar disk center is done by a series of line-center and off-line-center filtering observation, according to the physical meaning of contribution fu...Three-dimensional (3D) image reconstruction of an Hoc flare near the solar disk center is done by a series of line-center and off-line-center filtering observation, according to the physical meaning of contribution function based on the line formation theory. The contribution function represents the contribution from stellar atmospheric layers to the emergent specific intensity and describes the depth distribution of escape photons. In this paper, an Hot flare of 26 March 2001 is used to illustrate the 3D line-of-sight reconstruction and its development.展开更多
By use of the 2-m Mcmath-Pierce telescope at Kitt Peak, the high-quality spectra of a plage with moderate brightness near the center of solar disk were obtained. The data include seven spectral lines, which are Hα, H...By use of the 2-m Mcmath-Pierce telescope at Kitt Peak, the high-quality spectra of a plage with moderate brightness near the center of solar disk were obtained. The data include seven spectral lines, which are Hα, Hβ, Call H and K lines and the infrared triplet. With the con- sideration of fine structures of solar plages, a two-component atmospheric model is constructed by keeping the cool component to be the quiet atmosphere. Three cases of the hot component are given for different filling factors where the temperature and density distribution are adjusted in or- der to reproduce the seven observed spectral profiles. We also briefly discuss the influence of the column density at the base of the corona, m_0, and the macro-turbulent velocity on the required filling factor and computed profiles. The two-component model is compared with precious one-component semi-empirical models. The limitation of the model is pointed out and further im- provement is indicated.展开更多
基金Supported by the National Aeronautics and Space Administration of US(Grant Nos.NNX0-7AH78G and NNX0-8AQ90G)the National Science Foundation of US(Grant Nos.ATM-0716950,ATM-0745744,and ATM-0936665)
文摘Recent studies showed a consistent pattern of changes in the sunspot structure associated with major flares: part of the peripheral penumbral regions vanishes during flares, and meanwhile, the umbral cores and/or inner penumbral regions are darkened. To understand the underlying physics of these observations, we compare the magnetic inclination angle in the decayed peripheral and the enhanced inner penumbral regions before and after the 4B/X3.4 flare of 2006 December 13 by using the high-resolution vector magnetograms from Hinode. We find that the mean inclination angle in the decayed penumbra increases after the flare while that in the enhanced penumbra near flaring neutral line decreases. The result confirms the previous idea that two components of a δ sunspot become connected after flares. As a result of new connection, peripheral penumbral fields change from a more inclined to a more vertical configuration and transverse fields in umbral core and inner penumbral regions increase substantially (Liu et al. 2005). The flare-associated changes of Doppler width as well as other parameters (the transverse field strength, continuum intensity and filling factor) are also presented.
基金the National Natural Science Foundation of China (Grant No. 19773016) the National Basic Research Foundation of China "973" (Grant No. G2000078401).
文摘Three-dimensional (3D) image reconstruction of an Hoc flare near the solar disk center is done by a series of line-center and off-line-center filtering observation, according to the physical meaning of contribution function based on the line formation theory. The contribution function represents the contribution from stellar atmospheric layers to the emergent specific intensity and describes the depth distribution of escape photons. In this paper, an Hot flare of 26 March 2001 is used to illustrate the 3D line-of-sight reconstruction and its development.
基金the National Natural Science Foundation of China (Grant No. 10025315) NKBRSF (Grant No. G2000078402) TRAPOYT.
文摘By use of the 2-m Mcmath-Pierce telescope at Kitt Peak, the high-quality spectra of a plage with moderate brightness near the center of solar disk were obtained. The data include seven spectral lines, which are Hα, Hβ, Call H and K lines and the infrared triplet. With the con- sideration of fine structures of solar plages, a two-component atmospheric model is constructed by keeping the cool component to be the quiet atmosphere. Three cases of the hot component are given for different filling factors where the temperature and density distribution are adjusted in or- der to reproduce the seven observed spectral profiles. We also briefly discuss the influence of the column density at the base of the corona, m_0, and the macro-turbulent velocity on the required filling factor and computed profiles. The two-component model is compared with precious one-component semi-empirical models. The limitation of the model is pointed out and further im- provement is indicated.
