scholarly journals A current-driven resistive instability and its nonlinear effects in simulations of coaxial helicity injection in a tokamak

2016 ◽  
Vol 23 (10) ◽  
pp. 102502 ◽  
Author(s):  
E. B. Hooper ◽  
C. R. Sovinec
Keyword(s):  
Nonlinear Effects ◽  
Helicity Injection ◽  
Coaxial Helicity Injection ◽  
A Current

Random Effects in a Nonlinear Vibration-Based Piezoelectric Energy Harvesting System

2019 ◽  
Vol 29 (04) ◽  
pp. 1950046 ◽  
Author(s):  
Tiago Leite Pereira ◽  
Aline Souza de Paula ◽  
Adriano Todorovic Fabro ◽  
Marcelo Amorim Savi
Keyword(s):  
Energy Harvesting ◽  
Random Effects ◽  
Nonlinear Effects ◽  
Signal Ratio ◽  
Chaotic Motions ◽  
Piezoelectric Energy ◽  
Power Spectral ◽  
Energy Harvesting System ◽  
Excitation Conditions ◽  
A Current

Vibration-based energy harvesting is of increasing importance and there is a current challenge to improve energy harvesting capacity exploiting nonlinear and random effects. This article investigates random effects in a nonlinear energy harvesting system. The system is represented by a magnetoelastic structure with two piezoceramic layers attached to the root of a cantilever beam, obtaining a bimorph generator. The energy harvesting system is subjected to three excitation conditions: pure harmonic, pure random and a combination of harmonic and random excitations. Noise-to-Signal Ratio (NSR) is employed to quantify different combinations of the forcing terms, establishing a procedure to evaluate the system performance. This approach is based on Power Spectral Density (PSD) of input and output signals. Numerical simulations are carried out, identifying the better combinations of harmonic and random excitations for energy harvesting purposes. Discussions about the influence of the kind of response are carried out evaluating the differences between periodic and chaotic motions. Conclusions show that both random and nonlinear effects can be tuned in order to enhance energy harvesting capacity.

Temperature and density characteristics of the Helicity Injected Torus-II spherical tokamak indicating closed flux sustainment using coaxial helicity injection

2008 ◽  
Vol 15 (8) ◽  
pp. 082501 ◽  
Author(s):  
W. T. Hamp ◽  
T. R. Jarboe ◽  
B. A. Nelson ◽  
R. G. O’Neill ◽  
R. Raman ◽  
...  
Keyword(s):  
Spherical Tokamak ◽  
Helicity Injection ◽  
Coaxial Helicity Injection

Low Aspect Ratio Tokamak Formation and Sustainment by Coaxial Helicity Injection Current Drive

1995 ◽  
Vol 27 (3T) ◽  
pp. 333-336
Author(s):  
B. A. Nelson ◽  
T. R. Jarboe ◽  
D. J. Orvis ◽  
A. K. Martin ◽  
J. Xie ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Current Drive ◽  
Injection Current ◽  
Helicity Injection ◽  
Low Aspect Ratio ◽  
Coaxial Helicity Injection

Magnetic reconnection process in transient coaxial helicity injection

2013 ◽  
Vol 20 (9) ◽  
pp. 090702 ◽  
Author(s):  
F. Ebrahimi ◽  
E. B. Hooper ◽  
C. R. Sovinec ◽  
R. Raman
Keyword(s):  
Magnetic Reconnection ◽  
Helicity Injection ◽  
Reconnection Process ◽  
Coaxial Helicity Injection

scholarly journals NSTX Plasma Start-Up Using Transient Coaxial Helicity Injection

2007 ◽  
Vol 52 (3) ◽  
pp. 393-397 ◽  
Author(s):  
D. Mueller ◽  
R. Raman ◽  
M. G. Bell ◽  
T. R. Jarboe ◽  
B. LeBlanc ◽  
...  
Keyword(s):  
Helicity Injection ◽  
Start Up ◽  
Coaxial Helicity Injection

scholarly journals Simulation of multi-pulse coaxial helicity injection in the Sustained Spheromak Physics Experiment

2018 ◽  
Vol 25 (3) ◽  
pp. 032503 ◽  
Author(s):  
J. B. O'Bryan ◽  
C. A. Romero-Talamás ◽  
S. Woodruff
Keyword(s):  
Helicity Injection ◽  
Coaxial Helicity Injection ◽  
Physics Experiment

scholarly journals Application of Townsend avalanche theory to tokamak startup by coaxial helicity injection

2017 ◽  
Vol 58 (1) ◽  
pp. 016013 ◽  
Author(s):  
K.C. Hammond ◽  
R. Raman ◽  
F.A. Volpe
Keyword(s):  
Helicity Injection ◽  
Coaxial Helicity Injection
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