Authors: Momchil E. Molnar (HAO), Roberto Casini (HAO)

The Helium I 1083 nm atomic line can be utilized to infer properties of the solar coronal magnetic field through the action of the unsaturated Hanle effect. The He I 1083.0 nm is uniquely positioned for this measurement as it is sensitive to the magnetic field strengths observed in the solar corona — the Hanle effect at those magnetic field strength regime creates linear polarization signatures on the order of a few percent of the line intensity. Furthermore, the He I 1083 nm line has been observed everpresently in erupting prominences associated with CMEs.

We present modeling of the He I 1083 nm polarimetric signatures of realistic rMHD models of solar prominence eruptions from Fan (2017), extending our previous work on analytical models of coronal flux ropes. Our results show that the deviation of purely radial linear polarization of the He I 1083 nm line is strongly correlated with the local longitudinal coronal magnetic field. We also present observational results on the observability of erupting prominences in the He I 1083 nm from the uCOMP observatories, showing its extended utility throughout the corona. We how a modest spaceborne coronagraph with 20-cm aperture could be used for routine Hanle magnetic field measurements of erupting prominences.

The findings presented in this submission demonstrate the possibility for coronal magnetic field diagnostics readily available with current instrumentation technology based on the Hanle effect that could enable direct measures of the CME magnetic field.