scholarly journals Flows along arch filaments observed in the GRIS ‘very fast spectroscopic mode’

2016 ◽  
Vol 12 (S327) ◽  
pp. 28-33
Author(s):  
S. J. González Manrique ◽  
C. Denker ◽  
C. Kuckein ◽  
A. Pastor Yabar ◽  
M. Collados ◽  
...  
Keyword(s):  
Near Infrared ◽  
Solar Surface ◽  
Dynamic Processes ◽  
Solar Telescope ◽  
The Sun ◽  
Line Profiles ◽  
Filament System ◽  
Solar Instruments ◽  
Multiple Component ◽  
New Generation

AbstractA new generation of solar instruments provides improved spectral, spatial, and temporal resolution, thus facilitating a better understanding of dynamic processes on the Sun. High-resolution observations often reveal multiple-component spectral line profiles, e.g., in the near-infrared He i 10830 Å triplet, which provides information about the chromospheric velocity and magnetic fine structure. We observed an emerging flux region, including two small pores and an arch filament system, on 2015 April 17 with the ‘very fast spectroscopic mode’ of the GREGOR Infrared Spectrograph (GRIS) situated at the 1.5-meter GREGOR solar telescope at Observatorio del Teide, Tenerife, Spain. We discuss this method of obtaining fast (one per minute) spectral scans of the solar surface and its potential to follow dynamic processes on the Sun. We demonstrate the performance of the ‘very fast spectroscopic mode’ by tracking chromospheric high-velocity features in the arch filament system.

LOCNES: A solar telescope to study the Sun-as-a-star activity in the near infrared

2020 ◽  
Author(s):  
Riccardo U. Claudi ◽  
Adriano Ghedina ◽  
Emanuele Pace ◽  
Anna Maria Di Giorgio ◽  
Valentina D'Orazi ◽  
...  
Keyword(s):  
Near Infrared ◽  
Solar Telescope ◽  
The Sun ◽  
Star Activity

The Interpretation of Line Profiles

1977 ◽  
Vol 36 ◽  
pp. 191-215
Author(s):  
G.B. Rybicki
Keyword(s):  
Magnetic Fields ◽  
Atomic Physics ◽  
Velocity Fields ◽  
Spectral Lines ◽  
Inhomogeneous Structure ◽  
The Sun ◽  
Line Profiles ◽  
Physical Phenomena

Observations of the shapes and intensities of spectral lines provide a bounty of information about the outer layers of the sun. In order to utilize this information, however, one is faced with a seemingly monumental task. The sun’s chromosphere and corona are extremely complex, and the underlying physical phenomena are far from being understood. Velocity fields, magnetic fields, Inhomogeneous structure, hydromagnetic phenomena – these are some of the complications that must be faced. Other uncertainties involve the atomic physics upon which all of the deductions depend.

scholarly journals Solar structure and evolution

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Jørgen Christensen-Dalsgaard
Keyword(s):  
Solar Surface ◽  
Solar Neutrinos ◽  
Solar Interior ◽  
Stellar Structure ◽  
The Sun ◽  
Physical Processes ◽  
Solar Evolution ◽  
Internal Properties ◽  
Atmospheric Phenomena

AbstractThe Sun provides a critical benchmark for the general study of stellar structure and evolution. Also, knowledge about the internal properties of the Sun is important for the understanding of solar atmospheric phenomena, including the solar magnetic cycle. Here I provide a brief overview of the theory of stellar structure and evolution, including the physical processes and parameters that are involved. This is followed by a discussion of solar evolution, extending from the birth to the latest stages. As a background for the interpretation of observations related to the solar interior I provide a rather extensive analysis of the sensitivity of solar models to the assumptions underlying their calculation. I then discuss the detailed information about the solar interior that has become available through helioseismic investigations and the detection of solar neutrinos, with further constraints provided by the observed abundances of the lightest elements. Revisions in the determination of the solar surface abundances have led to increased discrepancies, discussed in some detail, between the observational inferences and solar models. I finally briefly address the relation of the Sun to other similar stars and the prospects for asteroseismic investigations of stellar structure and evolution.

scholarly journals Dynamic model of speed control through ring gears in a device with a multistage gear differentials and closed-loop hydraulic systems

2020 ◽  
Vol 99 (3) ◽  
pp. 102-111
Author(s):  
O. Strilets
Keyword(s):  
Computer Simulation ◽  
Quantitative Analysis ◽  
Closed Loop ◽  
Speed Control ◽  
Dynamic Processes ◽  
The Sun ◽  
Hydraulic Systems ◽  
Lagrange Method ◽  
Last Stage ◽  
Gear Differential

The dynamic processes in the device for speed control with multistage gear differential and closed-loop hydraulic systems through ring gears have been studied for case when the leading link is the sun gear of the first stage, and the driven is a carrier of the last stage. For such a device, the equation of kinetic energy has been compiled and the dynamics equations have been obtained by the Lagrange method, which have been solved. The obtained results are the basis for further computer simulation on and quantitative analysis to assess the performance of such devices and select the necessary closed-loop hydraulic systems to control speed changes.

scholarly journals The Tor Vergata Synoptic Solar Telescope (TSST): A robotic, compact facility for solar full disk imaging

2020 ◽  
Vol 10 ◽  
pp. 58
Author(s):  
Luca Giovannelli ◽  
Francesco Berrilli ◽  
Daniele Calchetti ◽  
Dario Del Moro ◽  
Giorgio Viavattene ◽  
...  
Keyword(s):  
Solar Atmosphere ◽  
Space Weather ◽  
Coronal Mass Ejections ◽  
Low Cost ◽  
Optical Filter ◽  
Solar Telescope ◽  
The Sun ◽  
Weather Events ◽  
Line Observation ◽  
Full Disk

By the continuous multi-line observation of the solar atmosphere, it is possible to infer the magnetic and dynamical status of the Sun. This activity is essential to identify the possible precursors of space weather events, such as flare or coronal mass ejections. We describe the design and assembly of TSST (Tor Vergata Synoptic Solar Telescope), a robotic synoptic telescope currently composed of two main full-disk instruments, a Hα telescope and a Potassium (KI D1) magneto-optical filter (MOF)-based telescope operating at 769.9 nm. TSST is designed to be later upgraded with a second MOF channel. This paper describes the TSST concepts and presents the first light observation carried out in February 2020. We show that TSST is a low-cost robotic facility able to achieve the necessary data for the study of precursors of space weather events (using the magnetic and velocity maps by the MOF telescope) and fast flare detection (by the Hα telescope) to support Space Weather investigation and services.

scholarly journals Near-infrared broad-line profiles in low-redshift QSOs

1992 ◽  
Vol 395 ◽  
pp. 403 ◽  
Author(s):  
Keith L. Thompson
Keyword(s):  
Near Infrared ◽  
Broad Line ◽  
Line Profiles

scholarly journals Surface Abundances of Light Elements as Diagnostics of Transport Processes in the Sun and Solar-type stars

1990 ◽  
Vol 121 ◽  
pp. 437-448
Author(s):  
A. Baglin ◽  
Y. Lebreton
Keyword(s):  
Solar Surface ◽  
Rotation Velocity ◽  
Transport Processes ◽  
Physical Parameters ◽  
The Sun ◽  
Light Elements ◽  
Cosmic Abundance ◽  
Solar Type ◽  
The Moment ◽  
Slow Transport

AbstractObservations of the surface abundances of lithium, beryllium and helium-3 in the Sun and in solar-type stars of different ages should be interpreted in a coherent way. The abundance of lithium at the surface of a star decreases slowly with age; for stars of the same age it decreases with mass and a dependence on the rotation velocity is suggested. The solar surface lithium is depleted by a factor of 100 relative to the cosmic abundance while an He-3 enrichment of 15% at the solar surface during evolution is suggested.Observations favour the hypothesis of a slow transport process at work between the outer convective zone and the radiative interior of these stars. Orders of magnitude of the transport coefficient as well as its dependence upon the physical parameters can be inferred from surface abundances of light elements, but at the moment we are far from producing a completely consistent modelization.

scholarly journals Magnetoconvection Patterns in Rotating Convection Zones

1991 ◽  
Vol 130 ◽  
pp. 37-56
Author(s):  
Paul H. Roberts
Keyword(s):  
Convection Zone ◽  
Solar Surface ◽  
Giant Cells ◽  
Conclusive Evidence ◽  
The Other ◽  
The Sun ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
Entire Thickness ◽  
Convective Motions

AbstractIn addition to the well-known granulation and supergranulation of the solar convection zone (the “SCZ”), the presence of so-called “giant cells” has been postulated. These are supposed span the entire thickness of the SCZ and to stretch from pole to pole in a sequence of elongated cells like a “cartridge belt” or a bunch of “bananas” strung uniformly round the Sun. Conclusive evidence for the existence of such giant cells is still lacking, despite strenuous observational efforts to find them. After analyses of sunspot motion, Ribes and others believe that convective motions near the solar surface occurs in a pattern that is the antithesis of the cartridge belt: a system of “toroidal” or “doughnut” cells, girdling the Sun in a sequence that extends from one pole to the other. Galloway, Jones and Roberts have recently tried to meet the resulting theoretical challenge, with the mixed success reported in this paper.

Bioapplications and biotechnologies of upconversion nanoparticle-based nanosensors

The Analyst ◽  
2016 ◽  
Vol 141 (12) ◽  
pp. 3601-3620 ◽  
Author(s):  
Chengli Wang ◽  
Xiaomin Li ◽  
Fan Zhang
Keyword(s):  
Optical Properties ◽  
High Resistance ◽  
Near Infrared ◽  
Signal To Noise Ratio ◽  
Upconversion Nanoparticles ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Auto Fluorescence ◽  
New Generation ◽  
Narrow Emission

Upconversion nanoparticles (UCNPs), which can emit ultraviolet/visible (UV/Vis) light under near-infrared (NIR) excitation, are regarded as a new generation of nanoprobes because of their unique optical properties, including a virtually zero auto-fluorescence background for the improved signal-to-noise ratio, narrow emission bandwidths and high resistance to photo-bleaching.

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