sun: activity

Infrared lines as probes of solar magnetic features. XV. Evershed flow in cool, weak penumbral fields

Observations of Ti I lines at 2.2 micrometer show that the Evershed flow takes place in cool, almost horizontal channels with a low magnetic field strength (~500-900 G) that does not appear to change significantly across the penumbra. This property …

Infrared lines as probes of solar magnetic features. XIV. TI i and the cool components of sunspots

The first systematic observations of sunspot umbrae using the lines of the Ti Ii multiplet at 2.2 mu m are presented. Their diagnostic capabilities are investigated, developed and used to investigate the magnetic and velocity structure of a sunspot. …