scholarly journals Impact of magnetic topology on radial electric field profile in the scrape-off layer of the Large Helical Device

2016 ◽  
Vol 56 (9) ◽  
pp. 092002 ◽  
Author(s):  
Y. Suzuki ◽  
K. Ida ◽  
K. Kamiya ◽  
M. Yoshinuma ◽  
H. Tsuchiya ◽  
...  
Keyword(s):  
Electric Field ◽  
Radial Electric Field ◽  
Field Profile ◽  
Magnetic Topology ◽  
Electric Field Profile

Modelling of radial electric field profile for different divertor configurations

2006 ◽  
Vol 48 (9) ◽  
pp. 1425-1435 ◽  
Author(s):  
V Rozhansky ◽  
E Kaveeva ◽  
S Voskoboynikov ◽  
G Counsell ◽  
A Kirk ◽  
...  
Keyword(s):  
Electric Field ◽  
Radial Electric Field ◽  
Field Profile ◽  
Electric Field Profile

scholarly journals Generation of the sheared radial electric field by a magnetic island structure

2004 ◽  
Vol 3 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Ana Mancic ◽  
Aleksandra Maluckov ◽  
Yokoyama Masayoshi ◽  
Okamoto Masao
Keyword(s):  
Electric Field ◽  
Local Treatment ◽  
Radial Electric Field ◽  
Model Parameters ◽  
Field Region ◽  
Field Profile ◽  
Magnetic Island ◽  
Island Structure ◽  
Non Local ◽  
Electric Field Profile

The effect of the presence of a magnetic island structure on the am bipolar radial electric field is studied in the context of the belt island model. It is shown that the sheared radial electric field region exists on the island position. Depending on the model parameters, the single (ion root) or multiple (one ion and two electron roots) solutions for the radial electric field are obtained at different radial positions. The radially non-local treatment is developed proposing the steady-state plasma conditions. The numerical calculations show that the diffusion of the radial electric field is significant only near the island boundaries. As a result the discontinuities in the am bipolar electric field profile are smoothed.

Electric-field profile and current control of a long epitaxial GaAs n layer

1972 ◽  
Vol 8 (4) ◽  
pp. 93 ◽  
Author(s):  
G.A. Swartz ◽  
A. Gonzalez ◽  
A. Dreeben
Keyword(s):  
Electric Field ◽  
Current Control ◽  
Field Profile ◽  
Epitaxial Gaas ◽  
Electric Field Profile

scholarly journals Electric potential differences across auroral generator interfaces

2013 ◽  
Vol 31 (2) ◽  
pp. 251-261 ◽  
Author(s):  
J. De Keyser ◽  
M. Echim
Keyword(s):  
Electric Field ◽  
High Altitude ◽  
Electric Fields ◽  
Electric Potential ◽  
Equilibrium Configuration ◽  
Potential Difference ◽  
Field Profile ◽  
Electric Potential Difference ◽  
Electric Field Profile

Abstract. Strong localized high-altitude auroral electric fields, such as those observed by Cluster, are often associated with magnetospheric interfaces. The type of high-altitude electric field profile (monopolar, bipolar, or more complicated) depends on the properties of the plasmas on either side of the interface, as well as on the total electric potential difference across the structure. The present paper explores the role of this cross-field electric potential difference in the situation where the interface is a tangential discontinuity. A self-consistent Vlasov description is used to determine the equilibrium configuration for different values of the transverse potential difference. A major observation is that there exist limits to the potential difference, beyond which no equilibrium configuration of the interface can be sustained. It is further demonstrated how the plasma densities and temperatures affect the type of electric field profile in the transition, with monopolar electric fields appearing primarily when the temperature contrast is large. These findings strongly support the observed association of monopolar fields with the plasma sheet boundary. The role of shear flow tangent to the interface is also examined.

Transport parameters and electric field profile in amorphous silicon solar cells

1991 ◽  
Vol 23 (2-4) ◽  
pp. 273-281
Author(s):  
R. Könenkamp ◽  
S. Muramatsu ◽  
H. Itoh ◽  
S. Matsubara ◽  
T. Shimada
Keyword(s):  
Solar Cells ◽  
Electric Field ◽  
Amorphous Silicon ◽  
Silicon Solar Cells ◽  
Field Profile ◽  
Transport Parameters ◽  
Electric Field Profile

Effect of the Electric Field Profile on the Accuracy of E-FISH Measurements in Ionization Waves

2021 ◽  
Author(s):  
Tat Loon Chng ◽  
David Z. Pai ◽  
Olivier Guaitella ◽  
Svetlana M Starikovskaia ◽  
Anne Bourdon
Keyword(s):  
Electric Field ◽  
Intermediate Phase ◽  
Second Harmonic ◽  
Strong Dependence ◽  
Field Profile ◽  
Test Configuration ◽  
True Value ◽  
Field Evolution ◽  
Electric Field Profile ◽  
Fish Signal

Abstract Electric field induced second harmonic (E-FISH) generation has emerged as a versatile tool for measuring absolute electric field strengths in time-varying, non-equilibrium plasmas and gas discharges. Yet recent work has demonstrated that the E-FISH signal, when produced with tightly focused laser beams, exhibits a strong dependence on both the length and shape of the applied electric field profile (along the axis of laser beam propagation). In this paper, we examine the effect of this dependence more meaningfully, by predicting what an E-FISH experiment would measure in a plasma, using 2D axisymmetric numerical fluid simulations as the true value. A pin-plane nanosecond discharge at atmospheric pressure is adopted as the test configuration, and the electric field evolution during the propagation of the ionization wave (IW) is specifically analyzed. We find that the various phases of this evolution (before and up to the front arrival, immediately behind the front and after the connection to the grounded plane) are quite accurately described by three unique electric field profile shapes, each of which produces a different response in the E-FISH signal. As a result, the accuracy of an E-FISH measurement is generally predicted to be comparable in the first and third phases of the IW evolution, and significantly poorer in the second (intermediate) phase. Fortunately, even though the absolute error in the field strength at certain time instants could be large, the overall shape of the field evolution curve is relatively well captured by E-FISH. Guided by the simulation results, we propose a procedure for estimating the error in the initial phase of the IW development, based on the presumption that the starting field profile mirrors that of its corresponding Laplacian conditions before evolving further. We expect that this approach may be readily generalized and applicable to other IW problems or phenomena, thus extending the utility of the E-FISH diagnostic.

scholarly journals Formation of the radial electric field profile in the WEST tokamak

2021 ◽  
Author(s):  
Laure Vermare ◽  
Pascale Hennequin ◽  
Cyrille Honore ◽  
Mathieu Peret ◽  
Guilhem Dif-Pradalier ◽  
...  
Keyword(s):  
Velocity Profile ◽  
Electric Field ◽  
Turbulent Transport ◽  
Radial Profile ◽  
Radial Electric Field ◽  
Turbulent Structures ◽  
The West ◽  
Transport Barrier ◽  
Deep Well ◽  
Electric Field Profile

Abstract Sheared flows are known to reduce turbulent transport by decreasing the correlation length and/or intensity of turbulent structures. The transport barrier that takes place at the edge during improved regimes such as H mode, corresponds to the establishment of a large shear of the radial electric field. In this context, the radial shape of the radial electric field or more exactly of the perpendicular $E\times B$ velocity appears as a key element in accessing improved confinement regimes. In this paper, we present the radial profile of the perpendicular velocity measured using Doppler back-scattering system at the edge of the plasma, dominated by the $E\times B$ velocity, during the first campaigns of the WEST tokamak. It is found that the radial velocity profile is clearly more sheared in LSN than in USN configuration for ohmic and low current plasmas ($B=3.7T$ and $q_{95}=4.7$), consistently with the expectation comparing respectively “favourable” versus “unfavourable” configuration. Interestingly, this tendency is sensitive to the plasma current and to the amount of additional heating power leading to plasma conditions in which the $E\times B$ velocity exhibits a deeper well in USN configuration. For example, while the velocity profile exhibits a clear and deep well just inside the separatrix concomitant with the formation of a density pedestal during L-H transitions observed in LSN configuration, deeper $E_r$ wells are observed in USN configuration during similar transitions with less pronounced density pedestal.

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