bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Second Flight of the Sunrise Balloon-borne Solar Observatory: Overview of Instrument Updates, the Flight, the Data, and First Results
Authors: Solanki S. K. , Riethmüller T. L. , Barthol P. , Danilovic S. , Deutsch W. , Doerr H.-P. , Feller A. , Gandorfer A. , Germerott D. , Gizon L. , Grauf B. , Heerlein K. , Hirzberger J. , Kolleck M. , Lagg A. , Meller R. , Tomasch G. , Noort M. van , Rodríguez J. Blanco , Blesa J. L. Gasent , Jiménez M. Balaguer , Iniesta J. C. Del Toro , Jiménez A. C. López , Suarez D. Orozco , Berkefeld T. , Halbgewachs C. , Schmidt W. , Álvarez-Herrero A. , Sabau-Graziati L. , Grande I. Pérez , Pillet V. Martínez , Card G. , Centeno R. , Knölker M. , Lecinski A. 
Published: March 2017

Abstract
The
Sunrise
balloon-borne solar observatory, consisting of a 1 m aperture telescope that provides a stabilized image to a UV filter imager and an imaging vector polarimeter, carried out its second science flight in 2013 June. It provided observations of parts of active regions at high spatial resolution, including the first high-resolution images in the Mg ii k line. The obtained data are of very high quality, with the best UV images reaching the diffraction limit of the telescope at 3000 Å after Multi-Frame Blind Deconvolution reconstruction accounting for phase-diversity information. Here a brief update is given of the instruments and the data reduction techniques, which includes an inversion of the polarimetric data. Mainly those aspects that evolved compared with the first flight are described. A tabular overview of the observations is given. In addition, an example time series of a part of the emerging active region NOAA AR 11768 observed relatively close to disk center is described and discussed in some detail. The observations cover the pores in the trailing polarity of the active region, as well as the polarity inversion line where flux emergence was ongoing and a small flare-like brightening occurred in the course of the time series. The pores are found to contain magnetic field strengths ranging up to 2500 G, and while large pores are clearly darker and cooler than the quiet Sun in all layers of the photosphere, the temperature and brightness of small pores approach or even exceed those of the quiet Sun in the upper photosphere.
Photospheric Response to an Ellerman Bomb-like Event—An Analogy of Sunrise/IMaX Observations and MHD Simulations
Authors: Danilovic S. , Solanki S. K. , Barthol P. , Gandorfer A. , Gizon L. , Hirzberger J. , Riethmüller T. L. , van Noort M. , Rodríguez J. Blanco , Del Toro Iniesta J. C. , Suárez D. Orozco , Schmidt W. , Pillet V. Martínez , Knölker M. 
Published: March 2017

Abstract
Ellerman Bombs are signatures of magnetic reconnection, which is an important physical process in the solar atmosphere. How and where they occur is a subject of debate. In this paper, we analyze Sunrise/IMaX data, along with 3D MHD simulations that aim to reproduce the exact scenario proposed for the formation of these features. Although the observed event seems to be more dynamic and violent than the simulated one, simulations clearly confirm the basic scenario for the production of EBs. The simulations also reveal the full complexity of the underlying process. The simulated observations show that the Fe i 525.02 nm line gives no information on the height where reconnection takes place. It can only give clues about the heating in the aftermath of the reconnection. However, the information on the magnetic field vector and velocity at this spatial resolution is extremely valuable because it shows what numerical models miss and how they can be improved.
Oscillations on Width and Intensity of Slender Ca ii H Fibrils from Sunrise/SuFI
Authors: Gafeira R. , Jafarzadeh S. , Solanki S. K. , Lagg A. , van Noort M. , Barthol P. , Rodríguez J. Blanco , del Toro Iniesta J. C. , Gandorfer A. , Gizon L. , Hirzberger J. , Knölker M. , Suárez D. Orozco , Riethmüller T. L. , Schmidt W. 
Published: March 2017

Abstract
We report the detection of oscillations in slender Ca ii H fibrils (SCFs) from high-resolution observations acquired with the Sunrise balloon-borne solar observatory. The SCFs show obvious oscillations in their intensity, but also their width. The oscillatory behaviors are investigated at several positions along the axes of the SCFs. A large majority of fibrils show signs of oscillations in intensity. Their periods and phase speeds are analyzed using a wavelet analysis. The width and intensity perturbations have overlapping distributions of the wave period. The obtained distributions have median values of the period of 32 ± 17 s and 36 ± 25 s, respectively. We find that the fluctuations of both parameters propagate in the SCFs with speeds of

km s−1 and

km s−1, respectively. Furthermore, the width and intensity oscillations have a strong tendency to be either in anti-phase or, to a smaller extent, in phase. This suggests that the oscillations of both parameters are caused by the same wave mode and that the waves are likely propagating. Taking all the evidence together, the most likely wave mode to explain all measurements and criteria is the fast sausage mode.
Kinematics of Magnetic Bright Features in the Solar Photosphere
Authors: Jafarzadeh S. , Solanki S. K. , Cameron R. H. , Barthol P. , Rodríguez J. Blanco , Iniesta J. C. del Toro , Gandorfer A. , Gizon L. , Hirzberger J. , Knölker M. , Pillet V. Martínez , Suárez D. Orozco , Riethmüller T. L. , Schmidt W. , Noort M. van 
Published: March 2017

Abstract
Convective flows are known as the prime means of transporting magnetic fields on the solar surface. Thus, small magnetic structures are good tracers of turbulent flows. We study the migration and dispersal of magnetic bright features (MBFs) in intergranular areas observed at high spatial resolution with Sunrise/IMaX. We describe the flux dispersal of individual MBFs as a diffusion process whose parameters are computed for various areas in the quiet-Sun and the vicinity of active regions from seeing-free data. We find that magnetic concentrations are best described as random walkers close to network areas (diffusion index,

), travelers with constant speeds over a supergranule (

), and decelerating movers in the vicinity of flux emergence and/or within active regions (

). The three types of regions host MBFs with mean diffusion coefficients of 130 km2 s−1, 80–90 km2 s−1, and 25–70 km2 s−1, respectively. The MBFs in these three types of regions are found to display a distinct kinematic behavior at a confidence level in excess of 95%.
Magneto-static Modeling from Sunrise/IMaX: Application to an Active Region Observed with Sunrise II
Authors: Wiegelmann T. , Neukirch T. , Nickeler D. H. , Solanki S. K. , Barthol P. , Gandorfer A. , Gizon L. , Hirzberger J. , Riethmüller T. L. , Noort M. van , Rodríguez J. Blanco , Iniesta J. C. Del Toro , Suárez D. Orozco , Schmidt W. , Pillet V. Martínez , Knölker M. 
Published: March 2017

Abstract
Magneto-static models may overcome some of the issues facing force-free magnetic field extrapolations. So far they have seen limited use and have faced problems when applied to quiet-Sun data. Here we present a first application to an active region. We use solar vector magnetic field measurements gathered by the IMaX polarimeter during the flight of the Sunrise balloon-borne solar observatory in 2013 June as boundary conditions for a magneto-static model of the higher solar atmosphere above an active region. The IMaX data are embedded in active region vector magnetograms observed with SDO/HMI. This work continues our magneto-static extrapolation approach, which was applied earlier to a quiet-Sun region observed with Sunrise I. In an active region the signal-to-noise-ratio in the measured Stokes parameters is considerably higher than in the quiet-Sun and consequently the IMaX measurements of the horizontal photospheric magnetic field allow us to specify the free parameters of the model in a special class of linear magneto-static equilibria. The high spatial resolution of IMaX (110–130 km, pixel size 40 km) enables us to model the non-force-free layer between the photosphere and the mid-chromosphere vertically by about 50 grid points. In our approach we can incorporate some aspects of the mixed beta layer of photosphere and chromosphere, e.g., taking a finite Lorentz force into account, which was not possible with lower-resolution photospheric measurements in the past. The linear model does not, however, permit us to model intrinsic nonlinear structures like strongly localized electric currents.
A New MHD-assisted Stokes Inversion Technique
Authors: Riethmüller T. L. , Solanki S. K. , Barthol P. , Gandorfer A. , Gizon L. , Hirzberger J. , Noort M. van , Rodríguez J. Blanco , Iniesta J. C. Del Toro , Suárez D. Orozco , Schmidt W. , Pillet V. Martínez , Knölker M. 
Published: March 2017

Abstract
We present a new method of Stokes inversion of spectropolarimetric data and evaluate it by taking the example of a Sunrise/IMaX observation. An archive of synthetic Stokes profiles is obtained by the spectral synthesis of state-of-the-art magnetohydrodynamics (MHD) simulations and a realistic degradation to the level of the observed data. The definition of a merit function allows the archive to be searched for the synthetic Stokes profiles that best match the observed profiles. In contrast to traditional Stokes inversion codes, which solve the Unno–Rachkovsky equations for the polarized radiative transfer numerically and fit the Stokes profiles iteratively, the new technique provides the full set of atmospheric parameters. This gives us the ability to start an MHD simulation that takes the inversion result as an initial condition. After a relaxation process of half an hour solar time we obtain physically consistent MHD data sets with a target similar to the observation. The new MHD simulation is used to repeat the method in a second iteration, which further improves the match between observation and simulation, resulting in a factor of 2.2 lower mean

value. One advantage of the new technique is that it provides the physical parameters on a geometrical height scale. It constitutes a first step toward inversions that give results consistent with the MHD equations.
Excentrée ou excentrique ?
Authors: Dormoy-Rajramanan Christelle , Jeanpierre Laurent 
Published: March 2017

À partir de l’étude du département de science politique de « Vincennes », de 1969 à 1980, cet article propose d’enrichir l’histoire de la discipline grâce à la prise en compte : des institutions secondaires, qui en sont parties prenantes ; du département d’enseignement comme unité d’analyse ; et de l’hétérogénéité des pratiques locales. Conduite à partir d’archives et de biographies d’enseignants-chercheurs, l’enquête insiste sur l’importance de l’État, du public étudiant et du capital social extra-universitaire des enseignants, comme paramètres d’analyse du développement des disciplines.
Les docteurs en science politique croient-ils en leur titre ?
Authors: Buton François , Lebaron Frédéric , Mariot Nicolas 
Published: March 2017

Cette note de recherche avance quelques résultats à partir d’une enquête par questionnaire menée auprès des docteurs en science politique ayant soutenu leur thèse dans les années 2000. Il s’agissait pour l’essentiel de demander à ces docteurs de retracer leur parcours doctoral et de porter un jugement sur les conditions de son déroulement. L’article s’intéresse principalement à un paradoxe : alors que la grande majorité des docteurs en science politique interrogés ont un emploi stable et se disent satisfaits des relations qu’ils ont pu avoir avec leur directeur de thèse, la moitié d’entre eux déconseillerait à de nouveaux arrivants d’entreprendre un travail de doctorat.
Modelling liquid water transport in snow under rain-on-snow conditions – considering preferential flow
Authors: Würzer Sebastian , Wever Nander , Juras Roman , Lehning Michael , Jonas Tobias 
Published: March 2017

Abstract. Rain on snow (ROS) has the potential to generate severe floods. Thus, precisely predicting the effect of an approaching ROS event on runoff formation is very important. Data analyses from past ROS events have shown that a snowpack experiencing ROS can either release runoff immediately or delay it considerably. This delay is a result of refreeze of liquid water and water transport, which in turn is dependent on snow grain properties but also on the presence of structures such as ice layers or capillary barriers. During sprinkling experiments, preferential flow was found to be a process that critically impacted the timing of snowpack runoff. However, current one-dimensional operational snowpack models are not capable of addressing this phenomenon. For this study, the detailed physics-based snowpack model SNOWPACK is extended with a water transport scheme accounting for preferential flow. The implemented Richards equation solver is modified using a dual-domain approach to simulate water transport under preferential flow conditions. To validate the presented approach, we used an extensive dataset of over 100 ROS events from several locations in the European Alps, comprising meteorological and snowpack measurements as well as snow lysimeter runoff data. The model was tested under a variety of initial snowpack conditions, including cold, ripe, stratified and homogeneous snow. Results show that the model accounting for preferential flow demonstrated an improved overall performance, where in particular the onset of snowpack runoff was captured better. While the improvements were ambiguous for experiments on isothermal wet snow, they were pronounced for experiments on cold snowpacks, where field experiments found preferential flow to be especially prevalent.
A Pilot Included Column Mean Vanishing Matrix
Authors: Kim Myungsup , Kwak Do Y. 
Published: March 2017

In this paper, we study a special matrix used in OFDM technology including the pilot vector. This is based on the property of 'column mean vanishing' and orthogonal columns. We study the spectral decomposition. Using this, we suggest a new method of generating such matrices. Numerical examples are included.
A plant‐derived dehydrorotenoid: a new inhibitor of hepatitis C virus entry
Authors: Bose Mihika , Kamra Mohini , Mullick Ranajoy , Bhattacharya Santanu , Das Saumitra , Karande Anjali A. 
Published: March 2017

Emergence of drug‐resistant viruses, high cost and adverse side‐effects associated with the standard therapy against hepatitis C virus (HCV) infection demonstrate the need for development of well tolerated and effective antivirals. We identified and chemically characterised the dehydrorotenoid boeravinone H, isolated from the herb Boerhavia diffusa, as a new inhibitor of HCV entry. The compound significantly inhibits the binding and entry of hepatitis C‐like particles (HCV‐LPs) in hepatoma cells in vitro with no apparent cytotoxicity. Boeravinone H inhibits the initial phase of HCV entry probably by acting directly on the viral particle. Importantly, the compound prevents HCV entry and infection in cell culture (ex vivo). Thus, boeravinone H is a potential antiviral agent for the prevention and control of HCV infection.
Development of a near‐infrared balloon‐borne camera for dayside and sunlit auroral observations
Authors: Zhou X.‐Y. , Lummerzheim D. , Gladstone R. , Rafol S. B. , Gunapala S. , He Y.‐T. , Hampton D. 
Published: March 2017

AbstractImaging aurora in daylight is a difficult and challenging task. The brightness of the sunlit atmosphere overwhelms the auroral emissions at visible wavelengths. Modeling of atmospheric brightness suggests that the contrast between auroral brightness and sky brightness makes it possible to image the aurora at near‐infrared (NIR) wavelengths from sufficient altitudes. Preliminary experiments confirmed that the auroral N2+ Meinel emissions at about 1100 nm are bright enough to be extracted from atmospheric background brightness during daylight at about 40 km of a balloon altitude, which lead to the development of a high‐performance NIR InGaAs camera that can be flown on a high‐altitude and long‐duration balloon. Auroral observations from such a platform are highly accommodated to current space missions (such as Time History of Events and Macroscale Interactions during Substorms/Acceleration Reconnection Turbulence and Electrodynamics of Moon's Interaction with the Sun, Magnetospheric Multiscale, Cluster, Geotail, and Defense Meteorological Satellite Program) and many ground‐based measurements and will enhance the science return significantly.
Comment on “An improved coupling model for the lithosphere‐atmosphere‐ionosphere system” by Kuo et al. [2014]
Authors: Prokhorov B. E. , Zolotov O. V. 
Published: March 2017

AbstractThe lithosphere‐atmosphere‐ionosphere coupling problem is a challenge nowadays. It requires understanding of (a) the physical mechanism that is responsible for plasma disturbances generation at ionospheric heights, (b) the penetration of seismogenic impact from the ground into the ionosphere through the underlying neutral atmosphere, and (c) on‐the‐ground (in‐the‐ground) sources generation. Kuo et al. (2014) reported an improved model of lithosphere‐atmosphere‐ionosphere coupling that includes the ionosphere as well as the underlying neutral atmosphere (from the ground up to the ionosphere altitudes, i.e., 60–80 km above the Earth's surface). The main feature of the Kuo et al. (2014) approach is that they find ground‐to‐ionosphere currents from

system of equations. In contrast to Kuo et al. (2011), where well‐known
equations are used, Kuo et al. (2014) looks better as it does not require the knowledge of electric conductivity σ profile. In this paper we show that the Kuo et al. (2014) equations can be obtained as a special case of the Kuo et al. (2011) ones, given the electric conductivity tensor is a spatially invariant scalar. Therefore, Kuo et al. (2014) formulation may not describe correctly electric currents flowing between the Earth and the ionosphere.
Simultaneous space and ground‐based observations of a plasmaspheric virtual resonance
Authors: Shi X. , Baker J. B. H. , Ruohoniemi J. M. , Hartinger M. D. , Frissell N. A. , Liu Jiang 
Published: March 2017

AbstractWe present simultaneous space and ground‐based observations of Pi2 pulsations which occurred during a substorm on 25 September 2014. The timeline for this event starts at ∼06:04 UT when the THEMIS probe D located inside the plasmasphere detected Pi2 pulsations in the electric and magnetic fields. Cross‐spectral analysis shows the azimuthal electric field and compressional magnetic field oscillated nearly in quadrature, highly suggestive of a standing fast‐mode wave. Simultaneous Pi2 observations from dayside and nightside ground magnetometers at low latitudes indicate a global wave mode. A latitudinal magnetometer chain on the nightside observed a phase reversal in the H component of the Pi2 pulsations when crossing the footprint of the plasmapause, estimated from THEMIS spacecraft measurements. Spectral analysis of data from ground magnetometers in this latitudinal chain showed fundamental and second harmonic spectral peaks in their H and D components. Similar pulsation signatures at comparable harmonic frequencies were observed by three midlatitude SuperDARN HF radars, both poleward and equatorward of the plasmapause ionospheric footprint. Finally, the longitudinal polarization pattern and azimuthal phase propagation of midlatitude Pi2 pulsations are consistent with previous observations of a plasmaspheric virtual resonance being excited by a longitudinally localized source near midnight.
The frictional strength of talc gouge in high‐velocity shear experiments
Authors: Chen Xiaofeng , Elwood Madden Andrew S. , Reches Ze'ev 
Published: March 2017

AbstractTalc is present in several large‐scale fault zones worldwide and is mineralogically stable at temperature of the upper crust. It is therefore necessary to gain a better understanding of the frictional behavior of talc under a wide range of slip velocity conditions occurring during the seismic cycle. We analyzed the frictional and structural characteristics of room‐dry and water‐saturated talc gouge by shear experiments on a confined gouge layer at slip velocity range of 0.002–0.66 m/s and normal stress up to 4.1 MPa. Room‐dry talc showed a distinct slip‐strengthening with the initial friction coefficient of μ ~ 0.4 increased systematically to μ ~ 1 at slip distance D > 1 m. Room‐dry talc also displayed velocity‐strengthening at slip distances shorter than 1 m. The water‐saturated talc gouge displayed systematic low frictional strength of μ = 0.1–0.3 for the entire experimental range, with clear velocity‐strengthening behavior with positive (a‐b) values (rate dependence parameter of rate and state friction) of 0.01–0.04. The microstructural analyses revealed distributed shear and systematic dilation (up to 50%) for the room‐dry talc, in contrast to the extreme slip localization and strong shear compaction for water‐saturated talc. We propose that talc frictional strength is controlled by lubrication along cleavage surfaces that is facilitated by adsorbed water (room‐dry) and surplus water (water‐saturated). This mechanism can explain our experimental observations of slip‐strengthening and velocity‐strengthening for both types of talc gouge, as well as other clay minerals. It is thus expected that talc presence in fault zones would enhance creep and inhibit unstable slip.
Rip currents and alongshore flows in single channels dredged in the surf zone
Authors: Moulton Melissa , Elgar Steve , Raubenheimer Britt , Warner John C. , Kumar Nirnimesh 
Published: March 2017

AbstractTo investigate the dynamics of flows near nonuniform bathymetry, single channels (on average 30 m wide and 1.5 m deep) were dredged across the surf zone at five different times, and the subsequent evolution of currents and morphology was observed for a range of wave and tidal conditions. In addition, circulation was simulated with the numerical modeling system COAWST, initialized with the observed incident waves and channel bathymetry, and with an extended set of wave conditions and channel geometries. The simulated flows are consistent with alongshore flows and rip‐current circulation patterns observed in the surf zone. Near the offshore‐directed flows that develop in the channel, the dominant terms in modeled momentum balances are wave‐breaking accelerations, pressure gradients, advection, and the vortex force. The balances vary spatially, and are sensitive to wave conditions and the channel geometry. The observed and modeled maximum offshore‐directed flow speeds are correlated with a parameter based on the alongshore gradient in breaking‐wave‐driven‐setup across the nonuniform bathymetry (a function of wave height and angle, water depths in the channel and on the sandbar, and a breaking threshold) and the breaking‐wave‐driven alongshore flow speed. The offshore‐directed flow speed increases with dissipation on the bar and reaches a maximum (when the surf zone is saturated) set by the vertical scale of the bathymetric variability.