Chromospheric Flashes in a Solar Pore: Insights from Multi-line Spectropolarimetric Diagnostics

Abstract

Solar pores are strongly magnetized regions lacking a photospheric penumbra and characterized by predominantly vertical magnetic fields. We present a multi-line study of flashes in a solar pore using high-resolution observations from the Swedish 1-m Solar Telescope in Fe~\textsc{i}~6302~à , Ca~\textsc{ii}~8542~à and K, and H-${\hat{I}}^2$, complemented by (E)UV data from \textit{IRIS} and \textit{SDO}/AIA. Bisector analysis and spectral inversions with \textsc{SIR} and \textsc{NICOLE} were used to infer stratifications of temperature, line-of-sight velocity, and magnetic field. Flashes, confined to one half of the pore, exhibit cooler photospheric temperatures ($\hat{I}”T\approx 400$~K), stronger magnetic fields ($\hat{I}”B\approx 250$~G), larger inclinations ($\sim 25^{\circ }$ versus $\sim 18^{\circ }$), and persistent upflows ($\sim 0.5$~km~s${}^{-1}$) compared to the quiescent pore. They are co-spatial with enhanced 3- and 5-minute power in the photosphere, while only 3-minute power persists in the chromosphere. Flashes are detected down to $\sim 50\%$ line depth in Ca~\textsc{ii}~8542~à intensity and show central chromospheric upflows ($\sim 1$~km~s${}^{-1}$) flanked by strong downflows ($\sim 8$~km~s${}^{-1}$). Temperature enhancements reach $\sim 500$~K at $\log \ddot{I}„\approx -5$ and $\sim 2500$~K at $\log \ddot{I}„\approx -6$, with a bimodal velocity distribution. Flashes correspond one-to-one with radially outward running waves near the pore boundary (5--15~km~s${}^{-1}$). Strong Ca~\textsc{ii} core emission, occasional Stokes~$V$ reversals, and H-${\hat{I}}^2$ enhancements indicate that pore flashes are confined to the lower and mid-chromosphere, with little influence on higher atmospheric layers.

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