Characterization of horizontal flows around solar pores from high-resolution time series of images

Though there is increasing evidence linking the moat flow and the Evershed flow along the penumbral filaments, there is not a clear consensus regarding the existence of a moat flow around umbral cores and pores, and the debate is still open. Solar pores appear to be a suitable scenario to test the moat-penumbra relation as evidencing the direct interaction between the umbra and the convective plasma in the surrounding photosphere, without any intermediate structure in between. The present work studies solar pores based on high resolution ground-based and satellite observations. Local correlation tracking techniques have been applied to different-duration time series to analyze the horizontal flows around several solar pores. Our results establish that the flows calculated from different solar pore observations are coherent among each other and show the determinant and overall influence of exploding events in the granulation around the pores. We do not find any sign of moat-like flows surrounding solar pores but a clearly defined region of inflows surrounding them. The connection between moat flows and flows associated to penumbral filaments is hereby reinforced by this work.Comment: 10 pages, 10 figures, Accepted for publication in Astronomy and Astrophysics

Recurrent Coronal Jets Induced by Repetitively Accumulated Electric Currents

Three extreme-ultraviolet (EUV) jets recurred in about one hour on 2010 September 17 in the following magnetic polarity of active region 11106. The EUV jets were observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). The Helioseismic and Magnetic Imager (HMI) on board SDO measured the vector magnetic field, from which we derive the magnetic flux evolution, the photospheric velocity field, and the vertical electric current evolution. The magnetic configuration before the jets is derived by the nonlinear force-free field (NLFFF) extrapolation. We derive that the jets are above a pair of parasitic magnetic bipoles which are continuously driven by photospheric diverging flows. The interaction drove the build up of electric currents that we indeed observed as elongated patterns at the photospheric level. For the first time, the high temporal cadence of HMI allows to follow the evolution of such small currents. In the jet region, we found that the integrated absolute current peaks repetitively in phase with the 171 A flux evolution. The current build up and its decay are both fast, about 10 minutes each, and the current maximum precedes the 171 A by also about 10 minutes. Then, HMI temporal cadence is marginally fast enough to detect such changes. The photospheric current pattern of the jets is found associated to the quasi-separatrix layers deduced from the magnetic extrapolation. From previous theoretical results, the observed diverging flows are expected to build continuously such currents. We conclude that magnetic reconnection occurs periodically, in the current layer created between the emerging bipoles and the large scale active region field. It induced the observed recurrent coronal jets and the decrease of the vertical electric current magnitude.Comment: 10 pages, 7 figures, accepted for publication in A&

Variability in low Mars atmosphere's H2_2O concentration stimulated by solar cycle activity

Mars' thin, CO$_2$-rich atmosphere poses a unique puzzle involving composition, climate history, and habitability. This work explores the intrincate relationship between Mars' atmospheric variations and dynamic solar activity patterns. We focus on periodic oscillations in H$_2$O vapor and the Pectinton solar flux index in the $\lambda$ = 10.7 cm radio band, around the characteristic 11-year solar cycle. Periodic Mars activity was studied using data from Mars Express' SPICAM instrument spanning 2004-2018. The Lomb-Scargle Periodogram method was applied to analyze the power spectra of both signals around this period, calibrated using peaks associated with the seasonal Martian cycle. This method was validated by analyzing power spectra of chemical species abundances in Earth's atmosphere, obtained from the NRLMSISE 00 empirical model provided by the National Oceanic and Atmospheric Administration (NOAA). Model executions reproduced chemical abundance data for various atmospheric species (N$_2$, O$_2$, N, H$_2$, Ar, and He) at two reference heights (upper mesosphere and low ionosphere) over a 1961-2021 time span. Results suggest a connection between variability in H$_2$O vapor concentration in Mars' atmosphere and fluctuations in the Pectinton solar flux index. We propose the Lomb-Scargle Periodogram method as a heuristic for studying oscillatory activity in planetary atmospheres with non-uniformly sampled data. While our results provide valuable insights, further analysis, cross-referencing with data from different orbiters, is required to deepen our understanding of these findings in the fields of planetary climatology and atmospheric physics.Comment: 25 pages, 24 figures. Submitted to MNRA