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Previous studies have related surface temperature maps, obtained with theDoppler imaging (DI) technique, of LQ Hya with long-term photometry. We comparesurface magnetic field maps, obtained with the Zeeman Doppler imaging (ZDI)technique, with contemporaneous photometry, with the aim of quantifying thestar's magnetic cycle characteristics. We inverted Stokes IV spectropolarimetryinto magnetic field and surface brightness maps using a tomographic inversioncode that models high signal-to-noise ratio mean line profiles produced by theleast squares deconvolution (LSD) technique. The magnetic field and surfacebrightness maps reveal similar patterns to previous DI and ZDI studies:non-axisymmetric polar magnetic field structure, void of fields atmid-latitudes, and a complex structure in the equatorial regions. There is aweak but clear tendency of the polar structures to be linked with strong radialfield and the equatorial ones with the azimuthal. We find a polarity reversalin the radial field between 2016 and 2017 coincident with an activity minimumseen in the long-term photometry. The inverted field strengths cannot easily berelated with the observed spottedness, but we find that they are partiallyconnected with the retrieved field complexity. Comparing to globalmagnetoconvection models for rapidly rotating young Suns, this field topologyand dominance of the poloidal field component could be explained by a turbulentdynamo, where differential rotation does not play a major role (so calledalpha^2 Omega or alpha^2 dynamos), and axi- and non-axisymmetric modes areexcited simultaneously. The complex equatorial magnetic field structure couldarise from the twisted (helical) wreaths often seen in these simulations, whilethe polar feature would be connected to the mostly poloidal non-axisymmetriccomponent having a smooth spatial structure.

Topological changes in the magnetic field of LQ Hya during an activity minimum