The Visible Spectro-Polarimeter of the Daniel K. Inouye Solar Telescope

TL;DR

The DKIST ViSP is a versatile, high-resolution spectro-polarimeter capable of observing multiple wavelengths simultaneously, enabling advanced solar magnetic and plasma studies with unprecedented flexibility and precision.

Contribution

This paper introduces the design and capabilities of the DKIST ViSP, a novel, wavelength-versatile spectro-polarimeter for solar observations, and presents initial commissioning data.

Findings

ViSP can tune across 380-900 nm range for simultaneous multi-wavelength observations.

It enables new spectro-polarimetric diagnostics and high-resolution solar studies.

Preliminary data demonstrate its potential for solar magnetic and plasma research.

Abstract

The Daniel K. Inouye Solar Telescope (DKIST) Visible Spectro-Polarimeter (ViSP) is a traditional slit-scanning spectrograph, with the ability to observe solar regions up to a $120\times78~\mathrm{arcsec}^2$ area. The design implements dual-beam polarimetry, a polychromatic polarization modulator, a high-dispersion echelle grating, and three spectral channels that can be automatically positioned. A defining feature of the instrument is its capability to tune anywhere within the 380-900~nm range of the solar spectrum, allowing for a virtually infinite number of combinations of three wavelengths to be observed simultaneously. This enables the ViSP user to pursue well-established spectro-polarimetric studies of the magnetic structure and plasma dynamics of the solar atmosphere, as well as completely novel investigations of the solar spectrum. Within the suite of first-generation instruments at the DKIST, ViSP is the only wavelength-versatile spectro-polarimeter available to the scientific community. It was specifically designed to be a discovery instrument, for the exploration of new spectroscopic and polarimetric diagnostics, and to test improved models of polarized line formation, through high spatial-, spectral-, and temporal-resolution observations of the Sun's polarized spectrum. In this instrument article, we describe the science requirements and design drivers of ViSP, and we present preliminary science data collected during the commissioning of the instrument.