Semi-empirical Models of Spicule from Inversion of Ca ii 8542 ? Line

We study a solar spicule observed off-limb using high-resolution imaging spectroscopy in the Ca II 8542 \AA\ line obtained with CRisp Imaging SpectroPolarimeter (CRISP) on Swedish 1-m Solar Telescope. Using new version of non-LTE code NICOLE specifically developed for this problem we invert single- and double-peak profiles. This considers geometry computes atomic populations by solving 1D radiative transfer assuming vertical stratification. The inversion proceeds fitting spectral profiles at 14 different heights synthetic computed model along its length. Motivated appearance profiles, which exhibit two distinct emission features well separated wavelength, adopt double-component scenario. start from ansatz that parameters are practically constant axis each component, except density drop. Our results support attaining very good fits to entire set 14$\times$4 (14 4 times). show uniform temperature 9560 K, exponential decrease height scale $1000-2000$ km, counter-oriented line-of-sight velocities components reproduce all segments well. Analyses numerical response function reveals necessity inversions spectra multiple positions obtain height-dependent, degeneracy-free reliable limited number free parameters.