[en] Complete text of publication follows. The rotation averaged location of the heliospheric current sheet has been found to be systematically shifted southward for about three years in the late declining to minimum phase of each solar cycle. This behaviour, called now by the concept of the Bashful ballerina, has been shown to be valid at least during the active solar cycles of the last century since the late 1920s. The IHY CIP program number 67 'Steps of the Bashful Ballerina: Global structure of the Solar/Inner Heliospheric Magnetic Field' studies these interesting global solar developments and their heliospheric/magnetospheric consequences. Recently, Zhao et al have analysed the WSO solar magnetic observations and conclude that there is no southward shift in HCS or north-south difference in the heliospheric magnetic field during the late declining phase of solar cycle 23. In disagreement with these results, we now find, using the HMF observations at 1 AU and their coronal sources as given by the WSO PFSS model, that there is a similar but smaller southward shift of the HCS during solar cycle 23, as in all previous solar cycles. This is further verified by the direct observations of the HCS location by Ulysses during its third fast latitude scan pass in 2007. The smaller asymmetry in SC 23 is in agreement with an earlier observation based on long-term geomagnetic activity that solar hemispheric asymmetry is larger during highly active solar cycles.

[en] A simple phenomenology is developed for the decay and transport of turbulence in a constant-speed, uniformly expanding medium. The fluctuations are assumed to be locally incompressible, and either of the hydrodynamic or non-Alfvenic magnetohydrodynamic (MHD) type. In order to represent local effects of nonlinearities, a simple model of the Karman-Dryden type for locally homogeneous turbulent decay is adopted. A detailed discussion of the parameters of this familiar one-point hydrodynamic closure is given, which has been shown recently to be applicable to non-Alfvenic MHD as well. The effects of the large-scale flow and expansion are incorporated using a two-scale approach, in which assumptions of particular turbulence symmetries provide simplifications. The derived model is tractable and provides a basis for understanding turbulence in the outer heliosphere, as well as in other astrophysical applications. (Author)

[en] The program was based on simultaneous observations of the same solar region with the Universal Birefringent Filter (UBF) at the Vacuum Tower Telescope (VTT) and with the Big Dome BD Universal Spectrograph (USG). For the UBF images analysis it is referred to the June 13, 1980 RG 2502/2511 (N12-E11) observations. Selected pictures present the line profiles for H-alpha, H-beta, Mg-b1 and Na-D2 at some interesting pixels of the analyzed AR. The detailed photometric morphology of the observed active area and the longitudinal velocity field pattern are presented. A comparison with the corresponding UVSP data is given

[en] The dynamics of surges is investigated from the series of the Hsub(α)-filtergrams obtained 29 September 1980 at the Ussurijsk Solar station. For the data tpeatment+ the spline method is used. The values of velocities and accelerations of the surges are estimated. Possible models of their evolution are discussed

[en] It is shown that the differential rotation rates estimated with the use of weak remnants of magnetic fields measured at a very low resolution during the periods of low solar activity and in the regions of the photosphere with a very low density of new magnetic flux sources lie between the differential rotation values obtained with the aid of highly averaged sunspot data and from daily magnetic field measurements. The effects disturbing the smooth changes in solar rotation velocity values with heliographic latitude, seen clearly in the distribution of magnetic fields as solar differential rotation parabolas, are briefly discussed. The predominance is shown of fields of one polarity over fields of the opposite polarity in the formation of the characteristic distribution and disturbance patterns in the background fields. The sign of this polarity changes with the sign of the solar magnetic fields in the polar regions. (author). 7 figs., 14 refs

[en] We study the dynamics of large dust grains ∼>1 μm with orbits outside of the heliosphere (beyond 250 AU). Motion of the solar system through the interstellar medium (ISM) at a velocity of 26 km s^-1 subjects these particles to gas and Coulomb drag (grains are expected to be photoelectrically charged) as well as the Lorentz force and the electric force caused by the induction electric field. We show that to zeroth order the combined effect of these forces can be well described in the framework of the classical Stark problem: particle motion in a Keplerian potential subject to an additional constant force. Based on this analogy, we elucidate the circumstances in which the motion becomes unbound, and show that under local ISM conditions dust grains smaller than ∼100 μm originating in the Oort Cloud (e.g., in collisions of comets) beyond 10⁴ AU are ejected from the solar system under the action of the electric force. Orbital motion of larger, bound grains is described analytically using the orbit-averaged Hamiltonian approach and consists of orbital plane precession at a fixed semimajor axis, accompanied by the periodic variations of the inclination and eccentricity (the latter may approach unity in some cases). A more detailed analysis of the combined effect of gas and Coulomb drag shows it is possible to reduce particle semimajor axes, but that the degree of orbital decay is limited (a factor of several at best) by passages through atomic and molecular clouds, which easily eject small particles.

[en] We present the results from a full polarization study carried out with the Atacama Large Millimeter/submillimeter Array (ALMA) during the first Very Long Baseline Interferometry (VLBI) campaign, which was conducted in 2017 April in the λ3 mm and λ1.3 mm bands, in concert with the Global mm-VLBI Array (GMVA) and the Event Horizon Telescope (EHT), respectively. We determine the polarization and Faraday properties of all VLBI targets, including Sgr A*, M87, and a dozen radio-loud active galactic nuclei (AGNs), in the two bands at several epochs in a time window of 10 days. We detect high linear polarization fractions (2%–15%) and large rotation measures (RM > 10^3.3–10^5.5 rad m⁻²), confirming the trends of previous AGN studies at millimeter wavelengths. We find that blazars are more strongly polarized than other AGNs in the sample, while exhibiting (on average) order-of-magnitude lower RM values, consistent with the AGN viewing angle unification scheme. For Sgr A* we report a mean RM of (−4.2 ± 0.3) × 10⁵ rad m⁻² at 1.3 mm, consistent with measurements over the past decade and, for the first time, an RM of (–2.1 ± 0.1) × 10⁵ rad m⁻² at 3 mm, suggesting that about half of the Faraday rotation at 1.3 mm may occur between the 3 mm photosphere and the 1.3 mm source. We also report the first unambiguous measurement of RM toward the M87 nucleus at millimeter wavelengths, which undergoes significant changes in magnitude and sign reversals on a one year timescale, spanning the range from −1.2 to 0.3 × 10⁵ rad m⁻² at 3 mm and −4.1 to 1.5 × 10⁵ rad m⁻² at 1.3 mm. Given this time variability, we argue that, unlike the case of Sgr A*, the RM in M87 does not provide an accurate estimate of the mass accretion rate onto the black hole. We put forward a two-component model, comprised of a variable compact region and a static extended region, that can simultaneously explain the polarimetric properties observed by both the EHT (on horizon scales) and ALMA (which observes the combined emission from both components). These measurements provide critical constraints for the calibration, analysis, and interpretation of simultaneously obtained VLBI data with the EHT and GMVA.

No abstract available

[en] Analysis of adiabatic MHD wave propagation through a conductive isoothermal atmosphere in the presence of gravity and a horizontal magnetic field shows that in an atmosphere comprising three layers of temperature T1 greater than T2 greater than T3, oscillations can be trapped at certain frequencies in the middle layer. If that layer is the solar chromosphere, the trapped waves could have periods ranging from about 4 to 45 min. 6 references

[en] We observe that intergranular jets, originating in the intergranular space surrounding individual granules, tend to be associated with granular fragmentation, in particular, with the formation and evolution of a bright granular lane (BGL) within individual granules. The BGLs have recently been identified as vortex tubes by Steiner et al. We further discover the development of a well-defined bright grain located between the BGL and the dark intergranular lane to which it is connected. Signatures of a BGL may reach the lower chromosphere and can be detected in off-band Hα images. Simulations also indicate that vortex tubes are frequently associated with small-scale magnetic fields. We speculate that the intergranular jets detected in the New Solar Telescope (NST) data may result from the interaction between the turbulent small-scale fields associated with the vortex tube and the larger-scale fields existing in the intergranular lanes. The intergranular jets are much smaller and weaker than all previously known jet-like events. At the same time, they appear much more numerous than the larger events, leading us to the speculation that the total energy release and mass transport by these tiny events may not be negligible in the energy and mass-flux balance near the temperature minimum atop the photosphere. The study is based on the photospheric TiO broadband (1.0 nm) filter data acquired with the 1.6 m NST operating at the Big Bear Solar Observatory. The data set also includes NST off-band Hα images collected through a Zeiss Lyot filter with a passband of 0.025 nm.