1. Twist propagation in Hα surges Patricia Jibben and Richard C. Canfield 2004, ApJ, 610, Observation of the Molecular Zeeman Effect in the G Band A.Asensio Ramos et al., 2004, ApJ, 611, L Sep 27 雑誌会速報 J. Kiyohara

Twist propagation in Hα surges Patricia Jibben and Richard C. Canfield 2004, ApJ, 610, 1129 － The relationship between surge spin and the stored twist in the magnetic field was examined. － Hα spectroheliograms (Mees CCD Imaging Spectrograph) spectral range : Hα±10 Å 2”.3 pixel -1 spatial and 0.37 Å pixel -1 spectral resolution vector magnetogram (Haleakala Stokes Polarimeter) Fe I : and magnetogram － Active region selection criteria - change of the active region area ⊿ a/a>10% - δor βγδregion - relatively large area ( a > 500μh) - well sampled with MCCD and HSP - within ± 45°of central meridian → 396 surges were selected

velocity map white : red shift black : blue shift Hα map → handedness could be determined in 249 → 68% correlation between surge handedness and the hemisphere of the Sun Hα spectropheliograms and Doppler Shifts

HSP vector magnetograms and αmaps left : vector magnetogram right : αmap negative : dashed positive : solid α ＞ 0 : right-handed

－ Most of the surges tend to occur near the edge of a sunspot and near a boundary separating opposite signs of α. － A correlation between the stored twist in the magnetic field at the point of origin and handedness of the surge spin at the 99% confidence level. Of all the observed surges, only 26 surges could be determined both the handedness of the surge and the sign of α at its point of origin.

Interpretation Magnetic reconnection of twisted magnetic flux with less twisted flux explains the correlation. right-handed left-handed － energy release will accompany reconnection, and brightenings are a common feature of the observed events. － if the reconnected field lines do not have the same twist per unit length, post-reconnection twist propagation will take place.

Observation of the Molecular Zeeman Effect in the G Band A. Asensio Ramos et al., 2004, ApJ, 611, L61 Photospheric bright points observed in G band are seen with very high contrast. → Theoretical investigation (Uietenbroek et al. 2004) → This paper shows － first observational study ( 4304 Å Å ) NOAA0477 on 2003 Aug. 30 with ZIMPOL (Zurich Imaging Polarimeter) piezoelastic modulator + linear polarizer － radiative transfer calculations

Theoretical prediction of the G-band polarization in Sunspot calculation including both the atomic and CH lines calculation including only the CH lines calculation without including any stray-light contamination In one wavelength location near 4303 Å, the overlap of several magnetically sensitive and nonsensitive CH lines was predicted to produce a single-lobed Stokes V profile.

calculations observed V/I positive polarity observed V/I negative polarity

calculations observed V/I observed Q/I in penumbrae non negligible linear polarization

－ The observed polarization profiles confirm the previous theoretical prediction of the Zeeman effect in the G band. － Non-negligible Linear polarization was detected in both umbrae and penumbrae. － preliminary comparison V/I amplitude is smaller than the theoretical prediction (2000G) → an indication of the presence of horizontal inhomogeneities in th photospheric regions of sunspot umbrae coexisting within the spatiotemporal resolution element of the observation. → these inhomogeneities might be associated with the multitude of umbral dots. → linear polarization signal observed in sunspot umbrae could be an indication that the umbral dot component has inclined magnetic fields. － The theoretical interpretation of observations of the Zeeman effect in the G band offers a new diagnostic window for exploring the thermal and magnetic structuring of the solar photosphere. conclusion