Doppler backscattering systems on the Globus-M2 tokamak

2022 ◽  
Vol 17 (01) ◽  
pp. C01023
Author(s):  
A.Y. Yashin ◽  
V.V. Bulanin ◽  
V.K. Gusev ◽  
V.B. Minaev ◽  
A.V. Petrov ◽  
...  
Keyword(s):  
Normal Incidence ◽  
Single Frequency ◽  
Vacuum Vessel ◽  
Plasma Properties ◽  
Zonal Flows ◽  
Density Distributions ◽  
The Core ◽  
Alfven Eigenmodes ◽  
Pyramidal Horn ◽  
Specific Reason

Abstract Doppler backscattering (DBS) was successfully previously used on the Globus-M tokamak. The diagnostic was utilised in the form of either a single-frequency or a four-frequency dual homodyne system. It was used primarily for the study of zonal flows, filaments and Alfvén eigenmodes. These phenomena are worth being studied both on the periphery and in the core region of the plasma in a tokamak. For this specific reason two multifrequency DBS systems were installed on the upgraded Globus-M2 tokamak. The first four-frequency system with dual homodyne detection had already been used on the Globus-M tokamak and has lower probing frequencies which provide measurements from the periphery plasma. The second and new six-frequency DBS system was installed with a non-linear transmission line that was adapted to generate probing signals at frequencies 50, 55, 60, 65, 70 and 75 GHz. In general, the range of probing frequencies corresponds to the region of critical plasma densities from 5 × 1018 to 7 × 1019 m−3 at normal incidence. The pyramidal horn antennas are located inside the vacuum vessel with a special cardan-like rotator outside the camera so as to tilt antennas in the toroidal and poloidal directions. A previously developed code was applied to simulate 3D raytracing for all frequency channels. Calculations were carried out for different angles of incidence and for different electron density distributions in order to investigate the possibilities of the implementation of radial and poloidal correlation Doppler reflectometry. Examples of the DBS system application for study of plasma properties in the Globus-M2 tokamak are presented.

Physics analyses on the core plasma properties in the helical fusion DEMO reactor FFHR-d1

2014 ◽  
Vol 54 (4) ◽  
pp. 043010 ◽  
Author(s):  
J. Miyazawa ◽  
Y. Suzuki ◽  
S. Satake ◽  
R. Seki ◽  
Y. Masaoka ◽  
...  
Keyword(s):  
Plasma Properties ◽  
The Core ◽  
Core Plasma

Survey of Jupiter’s Plasma Disk from Juno Observations

2021 ◽  
Author(s):  
Fran Bagenal ◽  
Ezra Huscher ◽  
Robert Wilson ◽  
Frederic Allegrini ◽  
Robert Ebert
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Plasma Sheet ◽  
Radial Distance ◽  
Regular Structure ◽  
Plasma Properties ◽  
Density Distributions ◽  
Jovian System ◽  
Structure Density

<p>Using 30 inbound passes through the Jovian system, we combine measurements from the fields and particles instruments on the Juno spacecraft to survey the properties of Jupiter's plasma disk. Juno's orbit is particularly useful for exploring the variation in plasma conditions with latitude as well as radial distance (from ~10 to ~50 RJ). We present basic plasma properties (composition, density, temperature, velocity, magnetic field strength) to make maps of the plasma environment. Also show that on some of the 53-day orbits the plasma sheet has regular structure (density having roughly Gaussian distribution with latitude and decreasing with distance) but there are also highly irregular orbits with low or erratic density distributions.</p>

scholarly journals Effect of the electron redistribution on the nonlinear saturation of Alfvén eigenmodes and the excitation of zonal flows

2020 ◽  
Vol 86 (3) ◽  
Author(s):  
A. Biancalani ◽  
A. Bottino ◽  
P. Lauber ◽  
A. Mishchenko ◽  
F. Vannini
Keyword(s):  
Magnetic Field ◽  
Zonal Flow ◽  
Large Aspect Ratio ◽  
Nonlinear Saturation ◽  
Energetic Ions ◽  
Electron Population ◽  
Zonal Flows ◽  
Particle In Cell ◽  
Alfven Eigenmodes ◽  
Reversed Shear

Numerical simulations of Alfvén modes driven by energetic particles are performed with the gyrokinetic (GK) global particle-in-cell code ORB5. A reversed shear equilibrium magnetic field is adopted. A simplified configuration with circular flux surfaces and large aspect ratio is considered. The nonlinear saturation of beta-induced Alfvén eigenmodes (BAE) is investigated. The roles of the wave–particle nonlinearity of the different species, i.e. thermal ions, electrons and energetic ions are described, in particular for their role in the saturation of the BAE and the generation of zonal flows. The nonlinear redistribution of the electron population is found to be important in increasing the BAE saturation level and the zonal flow amplitude.

Detection of Zero-Mean-Frequency Zonal Flows in the Core of a High-Temperature Tokamak Plasma

2006 ◽  
Vol 97 (12) ◽  
Author(s):  
D. K. Gupta ◽  
R. J. Fonck ◽  
G. R. McKee ◽  
D. J. Schlossberg ◽  
M. W. Shafer
Keyword(s):  
High Temperature ◽  
Tokamak Plasma ◽  
Zonal Flows ◽  
Mean Frequency ◽  
The Core

Single-frequency fibre laser with a cavity formed by Bragg gratings written in the core of an active composite fibre using KrF laser radiation (248 nm)

2019 ◽  
Vol 49 (12) ◽  
pp. 1112-1116
Author(s):  
O N Egorova ◽  
O I Medvedkov ◽  
E S Seregin ◽  
S A Vasil'ev ◽  
S E Sverchkov ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Bragg Gratings ◽  
Single Frequency ◽  
Fibre Laser ◽  
Composite Fibre ◽  
The Core ◽  
Krf Laser ◽  
Active Composite

Geophysical characteristics of the continental crust along the Lithoprobe Eastern Canadian Shield Onshore–Offshore Transect (ECSOOT): a review

2002 ◽  
Vol 39 (5) ◽  
pp. 569-587 ◽  
Author(s):  
Jeremy Hall ◽  
Keith E Louden ◽  
Thomas Funck ◽  
Sharon Deemer
Keyword(s):  
Normal Incidence ◽  
Shear Zones ◽  
Canadian Shield ◽  
P Wave ◽  
Seismic Profiles ◽  
Grenville Province ◽  
Core Zone ◽  
The Core ◽  
Geodynamic Processes ◽  
Archean Crust

The Eastern Canadian Shield Onshore–Offshore Transect (ECSOOT) of the Lithoprobe program included 1200 km of normal-incidence seismic profiles and seven wide-angle seismic profiles across Archean and Proterozoic rocks of Labrador, northern Quebec, and the surrounding marine areas. Archean crust is 33–44 km thick. P-wave velocity increases downwards from 6.0 to 6.9 km/s. There is moderate crustal reflectivity, but the reflection Moho is unclear. Archean crust that stabilized in the Proterozoic is similar except for greater reflectivity and a well-defined Moho. Proterozoic crust has similar or greater thickness, variable lower crustal velocities, and strong crustal reflectivity. Geodynamic processes of Paleoproterozoic growth of the Canadian Shield are similar to those observed in modern collisional orogens. The suturing of the Archean Core Zone and Superior provinces involved whole-crustal shearing (top to west) in the Core Zone, linked to thin-skinned deformation in the New Quebec Orogen. The Torngat Orogen sutures the Nain Province to the Core Zone and reveals a crustal root, in which Moho descends to 55 km. It formed by transpression and survived because of the lack of postorogenic heating. Accretion of the Makkovik Province to the Nain Province involves delamination at the Moho and distributed strain in the juvenile arcs. Delamination within the lower crust characterizes the accretion of Labradorian crust in the southeastern Grenville Province. Thinning of the crust northwards across the Grenville Front is accentuated by Mesozoic extension that reactivates Proterozoic shear zones. The intrusion of the Mesoproterozoic Nain Plutonic Suite is attributed to a mantle plume ponding at the base of the crust.

Carbon Dioxide Transport and Sorption Behavior in Confined Coal Cores for Carbon Sequestration

2009 ◽  
Vol 12 (01) ◽  
pp. 124-136 ◽  
Author(s):  
Sinisha A. Jikich ◽  
Robert T. McLendon ◽  
Kal Seshadri ◽  
Gino Irdi ◽  
Duane H. Smith
Keyword(s):  
Carbon Dioxide ◽  
Coalbed Methane ◽  
Sorption Isotherms ◽  
Confining Pressure ◽  
Initial Distribution ◽  
Sorption Behavior ◽  
Carbon Dioxide Transport ◽  
Density Distributions ◽  
The Core ◽  
Carbon Dioxide Co2

Summary Measurements of sorption isotherms and transport properties of carbon dioxide (CO2) in coal cores are important for designing enhanced coalbed-methane/CO2-sequestration field projects. Sorption isotherms measured in the laboratory can provide the upper limit on the amount of CO2 that might be sorbed in these projects. Because sequestration sites will most likely be in unmineable coals, many of the coals will be deep and under considerable lithostatic and hydrostatic pressures. These lithostatic pressures may reduce the sorption capacities and/or transport rates significantly. Consequently, we have studied apparent sorption and diffusion in a coal core under confining pressure. A core from the important bituminous coal Pittsburgh #8 was kept under a constant, 3D effective stress; the sample was scanned by X-ray computer tomography (CT) before, then while, it sorbed CO2. Increases in sample density because of sorption were calculated from the CT images. Moreover, density distributions for small volume elements inside the core were calculated and analyzed. Qualitatively, the CT showed that gas sorption advanced at different rates in different regions of the core, and that diffusion and sorption progressed slowly. The amounts of CO2 sorbed were plotted vs. position (at fixed times) and vs. time (for various locations in the sample). The resulting sorption isotherms were compared to isotherms obtained from powdered coal from the same Pittsburgh #8 extended sample. The results showed that for this single coal at specified times, the apparent sorption isotherms were dependent on position of the volume element in the core and the distance from the CO2 source. Also, the calculated isotherms showed that less CO2 was sorbed than by a powdered (and unconfined) sample of the coal. Changes in density distributions during the experiment were also observed. After desorption, the density distribution of calculated volume elements differed from the initial distribution, suggesting hysteresis and a possible rearrangement of coal structure because of CO2 sorption.

scholarly journals Study of matter density distributions, elastic charge form factors and size radii for halo 11Be, 19C and 11Li nuclei

2018 ◽  
Vol 16 (36) ◽  
pp. 29-38
Author(s):  
Zaid M. Abbas
Keyword(s):  
Form Factors ◽  
Matter Density ◽  
Wave Functions ◽  
Saxon Potential ◽  
Radial Wave ◽  
Charge Form ◽  
Density Distributions ◽  
The Core ◽  
Core Part ◽  
Good Agreement

In this work, the calculation of matter density distributions, elastic charge form factors and size radii for halo 11Be, 19C and 11Li nuclei are calculated. Each nuclide under study are divided into two parts; one for core part and the second for halo part. The core part are studied using harmonic-oscillator radial wave functions, while the halo part are studied using the radial wave functions of Woods-Saxon potential. A very good agreement are obtained with experimental data for matter density distributions and available size radii. Besides, the quadrupole moment for 11Li are generated.

scholarly journals Inelastic electron scattering form factors involving the second excited 2+ level in the isotopes 50,54,52Cr

2019 ◽  
Vol 13 (28) ◽  
pp. 19-26
Author(s):  
Ghaith Naima Flaiyh
Keyword(s):  
Charge Density ◽  
Form Factors ◽  
Transition Density ◽  
Collective Modes ◽  
Inelastic Electron ◽  
Core Polarization ◽  
Density Distributions ◽  
The Core ◽  
Model Transition ◽  
Remarkable Agreement

An expression for the transition charge density is investigated where the deformation in nuclear collective modes is taken into consideration besides the shell model transition density. The inelastic longitudinal form factors C2 calculated using this transition charge density with excitation of the levels for Cr54,52,50 nuclei. In this work, the core polarization transition density is evaluated by adopting the shape of Tassie model together with the derived form of the ground state two-body charge density distributions (2BCDD's). It is noticed that the core polarization effects which represent the collective modes are essential in obtaining a remarkable agreement between the calculated inelastic longitudinal F(q)'s and those of experimental data.

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