The ViSP is an Echelle spectrograph designed to measure three different spectral regions (between 380 and 900nm) simultaneously. It will use the polarimetric capabilities of the Daniel K. Inouye Solar Telescope (DKIST) to measure the full Stokes parameters of the observed spectral lines.

The ViSP instrument is being designed and built at HAO. When becoming operational at the DKIST, ViSP will be the highest precision spectropolarimeter ever produced - with a spatial resolution of approximately 40 km at 600 nm and temporal resolution of 10s to achieve 10-3 polarimetric precision. The ViSP will also provide continuous coverage over its spectral range. Here is a short list of some required specifications:

  1. Wavelength range: 380–900 nm, 3 lines simultaneously
  2. Spatial resolution: 2× DKIST resolution, 0.07” at 630 nm
  3. Spatial FOV: 2’×2’
  4. Spectral resolution: ≤3.5 pm at 630 nm or R≥180 000
  5. Polarimetric capability: 10-3 Icont polarimetric signal in 10 s
  6. Simultaneous operation with other instruments

ViSP science will rely mainly on its polarimetric capabilities. Among its scientific uses are the study of the formation and decay of active regions, the small-scale evolution of the quiet Sun magnetism, the magnetic stability of prominences and filaments, the magnetic structure before/during flares and CME precursors, the topology and dynamics of Chromospheric structures and the development of filament eruptions.

However, the beauty of this ground-based instrument also lies in its versatility. ViSP will allow the exploration of the solar spectrum to investigate new spectral diagnostics and research opportunities. Some examples along these lines are: same-ion multi-line diagnostics, polarization signatures of the second solar spectrum, high precision measurement of the Hanle effect in molecular bands, turbulent E-field diagnostics using H I lines of the Balmer and Paschen series, high precision spectropolarimetry of the PRD (partial re-distribution) and isotropic effects in atomic lines, etc.

The Visible Spectro-Polarimeter