HAO Colloquium - ViSP and ChroMag: Two Different Views of Magnetic Field in the Solar Atmosphere

Speaker: Alfred de Wijn, HAO

Since the discovery that sunspots are highly magnetized by Hale in the early 1900s, magnetism has become increasingly important in our understanding of processes on the Sun and in the Heliosphere. Consequently, many current and planned solar observatories have instruments that are capable of diagnosing magnetic fields through spectro-polarimetry, i.e., the measurement of polarization in spectral lines formed in the solar atmosphere. The Visible SpectroPolarimeter (ViSP) of the new Daniel K. Inouye Solar Telescope and the Chromosphere and Prominence Magnetometer of the Coronal Solar Magnetism Observatory are two such instruments that could not be more dissimilar: one is a field-scanning spectrograph that observes a small field-of-view with exceedingly high spatial resolution, while the other is a wavelength-scanning filtergraph that observes the entire solar disk. I will review the history, importance, and challenges of measuring magnetic field in the solar atmosphere and the chromosphere in particular, and discuss the considerations that led to the very different designs of the two instruments.

Date and time: 
Wednesday, February 23, 2022 - 2:00pm to 3:00pm