Magnetic and Electric Field Diagnostics of Chromospheric Jets by Spectropolarimetric Observations of the H_I Paschen Lines

摘要

In order to study the magnetic and electric fields of chromospheric jets, we observed the full Stokes spectra of the Paschen series of neutral hydrogen in active region jets that took place at the solar limb on May 5, 2012. For the observations, we used the spectropolarimeter of the Domeless Solar Telescope at Hida observatory, Japan. Inversion of the Stokes spectra taking into account the effect of magnetic field on the energy structure and polarization of the hydrogen levels (including the Hanle effect and level-crossing effects) elucidates the magnetic field approximately aligned with the visible structure of the jets. In addition to the magnetic field, the energy structure and the polarization of the hydrogen levels is sensitive to electric field through the Stark effect, electric Hanle effect (analogous effect with the Hanle effect by magnetic field), and the level-crossing effects. Since, we found no definitive evidence of the polarization produced by the effect of electric field in the observed Stokes profiles, we derived upper limits of electric field felt by neutral atom moving across the magnetic field, and conclude that the velocity of the neutral atom perpendicular to the magnetic field was below several percents of the velocity bulk plasma motion.