scholarly journals The Solar Activity Monitor Network - SAMNet

2021 ◽  
Author(s):  
robertus erdelyi ◽  
Marianna Brigitta Korsos ◽  
Xin Huang ◽  
Yong Yang ◽  
Danielle Pizzey ◽  
...  
Keyword(s):  
Solar Activity ◽  
Solar Atmosphere ◽  
Lead Time ◽  
Optical Filter ◽  
Velocity Fields ◽  
Doppler Velocity ◽  
Spectral Bands ◽  
Full Capacity ◽  
The Individual ◽  
Lower Solar Atmosphere

The Solar Activity Magnetic Monitor (SAMM) Network (SAMNet) is a future UK-led international network of ground-based solar telescope stations. SAMNet, at its full capacity, will continuously monitor the Sun’s intensity, magnetic and Doppler velocity fields at multiple  heights in the solar atmosphere (from photosphere to upper chromosphere). Each SAMM sentinel will be equipped with a cluster of identical telescopes each with different magneto-optical filter (MOFs) to take observations in K~I, Na~D and Ca~I spectral bands. A subset of SAMM stations will have white-light coronagraphs and emission line coronal spectropolarimeters. The objectives of SAMNet are to provide observational data for the space weather research and forecast. The goal is to achieve an operationally sufficient lead time of e.g. flare warning of 2-8 hours, and provide much sought-after continuous synoptic maps (e.g., LoS magnetic and velocity fields, intensity) of the lower solar atmosphere with a spatial resolution limited only by seeing or diffraction limit, and with a cadence of 10 minutes. The individual SAMM sentinels will be connected into their master HQ hub where data received from all the slave stations will be automatically processed and flare warning issued up to 26 hrs in advance.

Influence of Magnetic Fields on Solar Hydrodynamics: Experimental Results

1977 ◽  
Vol 36 ◽  
pp. 143-180 ◽  
Author(s):  
J.O. Stenflo
Keyword(s):  
Solar Activity ◽  
Energy Balance ◽  
Magnetic Fields ◽  
Solar Atmosphere ◽  
General Problem ◽  
Solar Rotation ◽  
Active Regions ◽  
Physical Conditions ◽  
Dynamic Phenomena

It is well-known that solar activity is basically caused by the Interaction of magnetic fields with convection and solar rotation, resulting in a great variety of dynamic phenomena, like flares, surges, sunspots, prominences, etc. Many conferences have been devoted to solar activity, including the role of magnetic fields. Similar attention has not been paid to the role of magnetic fields for the overall dynamics and energy balance of the solar atmosphere, related to the general problem of chromospheric and coronal heating. To penetrate this problem we have to focus our attention more on the physical conditions in the ‘quiet’ regions than on the conspicuous phenomena in active regions.

The Characteristics of Thin Magnetic Flux Tubes in the Lower Solar Atmosphere Observed byHinode/SOT in the G band and in Ca ii H Bright Points

2017 ◽  
Vol 851 (1) ◽  
pp. 42 ◽  
Author(s):  
Jianping Xiong ◽  
Yunfei Yang ◽  
Chunlan Jin ◽  
Kaifan Ji ◽  
Song Feng ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Solar Atmosphere ◽  
Flux Tubes ◽  
Magnetic Flux Tubes ◽  
Lower Solar Atmosphere

Estimation of the Energy Flux of Torsional Alfvén Waves in the Lower Solar Atmosphere Based on Measurements of the Doppler Velocities

2021 ◽  
Vol 61 (7) ◽  
pp. 1035-1037
Author(s):  
Yu. T. Tsap ◽  
A. V. Stepanov ◽  
Yu. G. Kopylova ◽  
O. V. Khaneychuk ◽  
T. B. Goldvarg
Keyword(s):  
Solar Atmosphere ◽  
Energy Flux ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Lower Solar Atmosphere

A Variational Method for Filling in Missing Data in Doppler Velocity Fields

2021 ◽  
Author(s):  
VINCENT T. WOOD ◽  
ROBERT P. DAVIES-JONES ◽  
ALAN SHAPIRO
Keyword(s):  
Missing Data ◽  
Doppler Radar ◽  
Signal To Noise Ratio ◽  
Original Data ◽  
Radar Data ◽  
Velocity Fields ◽  
Doppler Velocity ◽  
Doppler Radar Data ◽  
Ground Clutter ◽  
Tornado Warnings

AbstractSingle-Doppler radar data are often missing in important regions of a severe storm due to low return power, low signal-to-noise ratio, ground clutter associated with normal and anomalous propagation, and missing radials associated with partial or total beam blockage. Missing data impact the ability of WSR-88D algorithms to detect severe weather. To aid the algorithms, we develop a variational technique that fills in Doppler velocity data voids smoothly by minimizing Doppler velocity gradients while not modifying good data. This method provides estimates of the analysed variable in data voids without creating extrema.Actual single-Doppler radar data of four tornadoes are used to demonstrate the variational algorithm. In two cases, data are missing in the original data, and in the other two, data are voided artificially. The filled-in data match the voided data well in smoothly varying Doppler velocity fields. Near singularities such as tornadic vortex signatures, the match is poor as anticipated. The algorithm does not create any velocity peaks in the former data voids, thus preventing false triggering of tornado warnings. Doppler circulation is used herein as a far-field tornado detection and advance-warning parameter. In almost all cases, the measured circulation is quite insensitive to the data that have been voided and then filled. The tornado threat is still apparent.

scholarly journals Magnetic reconnection resulting from flux emergence: implications for jet formation in the lower solar atmosphere?

2011 ◽  
Vol 535 ◽  
pp. A95 ◽  
Author(s):  
J. Y. Ding ◽  
M. S. Madjarska ◽  
J. G. Doyle ◽  
Q. M. Lu ◽  
K. Vanninathan ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Solar Atmosphere ◽  
Flux Emergence ◽  
Jet Formation ◽  
Lower Solar Atmosphere

Transmission of Signals Using White LEDs for VLC Application

MRS Advances ◽  
2016 ◽  
Vol 1 (55) ◽  
pp. 3661-3666 ◽  
Author(s):  
P. Louro ◽  
V. Silva ◽  
J. Costa ◽  
M. A. Vieira ◽  
M. Vieira
Keyword(s):  
Optical Filter ◽  
Visible Light Communication ◽  
Indoor Navigation ◽  
Optical Signals ◽  
White Leds ◽  
Indoor Location ◽  
Optical Channels ◽  
Wavelength Sensitivity ◽  
Location Algorithm ◽  
The Individual

ABSTRCTIn this paper a photodetector working as an active optical filter device is used to detect modulated visible optical signals for applications based on Visible Light Communication (VLC). The proposed application demonstrates the viability of indoor positioning using VLC technology established by the modulation of indoor ultra-bright RGB white LEDs. The signals of the internal red and blue chips of the white LEDs were modulated at specific frequencies and the generated photocurrent was measured by a pin-pin photodetector based on a-SiC:H/a-Si:H. This device operates as a visible optical filter with controlled wavelength sensitivity through the use of adequate optical biasing light. Thus it is able to detect different wavelengths which allow the detection of the individual components of the tri-chromatic white LED. This possibility is the basis for the indoor location algorithm. We demonstrate the possibility of decoding four transmission optical channels supplied by two different wavelengths of white LEDs modulated under different bit sequences. The identification of the signals received by the photodetector allows the location identification of the photodetector position and supplies indoor navigation.

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 Analysis of Convective Thunderstorm Split Cells in South-Eastern Romania

2013 ◽  
Vol 2013 ◽  
pp. 1-19 ◽  
Author(s):  
Daniel Carbunaru ◽  
Sabina Stefan ◽  
Monica Sasu ◽  
Victor Stefanescu
Keyword(s):  
Velocity Field ◽  
Velocity Fields ◽  
Severe Weather ◽  
Doppler Velocity ◽  
Doppler Weather Radar ◽  
Dynamic Features ◽  
South Eastern ◽  
Wind Profiles ◽  
Convective Cells ◽  
Splitting Process

The mesoscale configurations are analysed associated withthesplitting process of convective cells responsible for severe weather phenomena in the south-eastern part of Romania. The analysis was performed using products from the S-band Doppler weather radar located in Medgidia. The cases studied were chosen to cover various synoptic configurations when the cell splitting process occurs. To detect the presence and intensity of the tropospheric jet, the Doppler velocity field and vertical wind profiles derived from radar algorithms were used. The relative Doppler velocity field was used to study relative flow associated with convective cells. Trajectories and rotational characteristics associated with convective cells were obtained from reflectivity and relative Doppler velocity fields at various elevations. This analysis highlights the main dynamic features associated with the splitting process of convective cells: the tropospheric jet and vertical moisture flow associated with the configuration of the flow relative to the convective cells for the lower and upper tropospheric layers. These dynamic characteristics seen in the Doppler based velocity field and in the relative Doppler velocity field to the storm can indicate further evolution of convective developments, with direct implications to very short range forecast (nowcasting).

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