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Small-scale, newly emerging internetwork (IN) magnetic fields are considered a viable source of energy and mass for the solar chromosphere and possibly the corona. Multiple studies show that single events of flux emergence can indeed locally heat the low solar atmosphere through interactions of the upward propagating magnetic loops and the preexisting ambient field lines. However, the global impact of the newly emerging IN fields on the solar atmosphere is still unknown. In this paper, we study the spatiotemporal evolution of IN bipolar flux features and analyze their impact on the energetics and dynamics of the quiet-Sun atmosphere. We use high-resolution, multiwavelength, coordinated observations obtained with the Interface Region Imaging Spectrograph, Hinode, and the Solar Dynamics Observatory to identify emerging IN magnetic fields and follow their evolution. Our observational results suggest that only the largest IN bipoles are capable of heating locally the low solar atmosphere, while the global contribution of these bipoles appears to be marginal. However, the total number of bipoles detected and their impact estimated in this work is limited by the sensitivity level, spatial resolution, and duration of our observations. To detect smaller and weaker IN fields that would maintain the basal flux, and examine their contribution to the chromospheric heating, we will need higher resolution, higher sensitivity, and longer time series obtained with current and next-generation ground- and space-based telescopes.

Tran­sport opa­snog te­re­ta je­dan je od za­da­ta­ka je­di­ni­ca i usta­no­va Voj­ske Sr­bi­je. Zbog specifičnosti ove vr­ste tran­spor­ta, kao i oba­ve­za iz za­kon­ske re­gu­la­ti­ve ko­ja uređuje ovu oblast, li­ca uključena u pro­ces pla­ni­ra­nja i re­a­li­za­ci­je tran­spor­ta dužna su da pre­du­zmu me­re ka­ko se ne bi do­go­dio ak­ci­dent­ni događaj. Radi pred­u­zi­ma­nja pre­ven­tiv­nih me­ra vrši se pro­ce­na ri­zi­ka. U Voj­sci Sr­bi­je naj­za­stu­plje­ni­ji je tran­sport naf­te i naft­nih de­ri­va­ta za po­tre­be je­di­ni­ca i usta­no­va. Pri­li­kom pla­ni­ra­nja tran­spor­ta vrši se iz­bor tra­se za kre­ta­nje vo­zi­la. U ra­du je opi­sa­na me­to­do­lo­gi­ja za iz­bor tra­se za tran­sport opa­snog te­re­ta i pri­me­na na kon­kret­nom slučaju u Voj­sci Sr­bi­je.

The purpose of this work is to show how to affect the most important factor of traffic safety - an individual, by using some technical solutions of satellite tracking of vehicles. By using units of the Land Forces as an example, a brief analysis of traffic safety for vehicles less than 5 years old has been performed. It is noticed that the number of traffic accidents with these vehicles involved has increased, so we tried to use one software package commercially available in order to show all advantages and disadvantages which could be noticed during this kind of vehicle tracking. The conclusion is that preventive vehicle tracking can improve traffic safety, but that a techno-economic analysis has to be done as well, in order to create all the necessary conditions for the introduction of this system in the units of the Serbian Armed Forces.

The heating of the solar chromosphere remains one of the most important questions in solar physics. Our current understanding is that small-scale internetwork (IN) magnetic fields play an important role as a heating agent. Indeed, cancellations of IN magnetic elements in the photosphere can produce transient brightenings in the chromosphere and transition region. These bright structures might be the signature of energy release and plasma heating, probably driven by the magnetic reconnection of IN field lines. Although single events are not expected to release large amounts of energy, their global contribution to the chromosphere may be significant due to their ubiquitous presence in quiet Sun regions. In this paper, we study cancellations of IN elements and analyze their impact on the energetics and dynamics of the quiet Sun atmosphere. We use high-resolution, multiwavelength, coordinated observations obtained with the Interface Region Imaging Spectrograph and the Swedish 1 m Solar Telescope (SST) to identify cancellations of IN magnetic flux patches and follow their evolution. We find that, on average, these events live for ∼3 minutes in the photosphere and ∼12 minutes in the chromosphere and/or transition region. Employing multi-line inversions of the Mg ii h and k lines, we show that cancellations produce clear signatures of heating in the upper atmospheric layers. However, at the resolution and sensitivity accessible to the SST, their number density still seems to be one order of magnitude too low to explain the global chromospheric heating. [ABSTRACT FROM AUTHOR]

Small-scale internetwork magnetic fields are important ingredients of the quiet Sun. In this paper we analyze how they appear and disappear on the solar surface. Using high resolution Hinode magnetograms, we follow the evolution of individual magnetic elements in the interior of two supergranular cells at the disk center. From up to 38 hr of continuous measurements, we show that magnetic flux appears in internetwork regions at a rate of 120 ± 3 Mx cm−2 day−1 (3.7 ± 0.4 × 1024 Mx day−1 over the entire solar surface). Flux disappears from the internetwork at a rate of 125 ± 6 Mx cm−2 day−1 (3.9 ± 0.5 × 1024 Mx day−1) through fading of magnetic elements, cancelation between opposite-polarity features, and interactions with network patches, which converts internetwork elements into network features. Most of the flux is lost through fading and interactions with the network, at nearly the same rate of about 50 Mx cm−2 day−1. Our results demonstrate that the sources and sinks of internetwork magnetic flux are well balanced. Using the instantaneous flux appearance and disappearance rates, we successfully reproduce the time evolution of the total unsigned flux in the two supergranular cells. [ABSTRACT FROM AUTHOR]

We report observational evidence of Lagrangian chaotic saddles in plasmas, given by the intersections of finite-time unstable and stable manifolds, using an ≈22h sequence of spacecraft images of the horizontal velocity field of solar photosphere. A set of 29 persistent objective vortices with lifetimes varying from 28.5 to 298.3 min are detected by computing the Lagrangian averaged vorticity deviation. The unstable manifold of the Lagrangian chaotic saddles computed for ≈11h exhibits twisted folding motions indicative of recurring vortices in a magnetic mixed-polarity region. We show that the persistent objective vortices are formed in the gap regions of Lagrangian chaotic saddles at supergranular junctions.